This application is based upon and claims the benefit of priority from the prior Japanese Patent Applications No. 2002-67259, filed Mar. 12, 2002; No. 2003-22480, filed Jan. 30, 2003, the entire contents of both of which are incorporated herein by reference.
1. Field of the Invention
The present invention relates to a silver halide photosensitive material. Particularly, the present invention relates to a silver halide photosensitive material that reconciles high photographic speed and low fog.
2. Description of the Related Art
The silver halide photosensitive material principally comprises a support and, superimposed thereon, a dispersion medium containing lightsensitive silver halide grains. Extensive investigations have been conducted for increasing the photographic speed of silver halide lightsensitive material. Increasing the inherent sensitivity of silver halide grains is very important for attaining an increase of the photographic speed of silver halide lightsensitive material. Various methods have been employed for increasing the inherent sensitivity of silver halides with respect to such silver halide grains.
For example, there have been employed a sensitivity enhancement wherein use is made of a chemical sensitizer such as sulfur, gold or a compound of a metal of Group VIII, a sensitivity enhancement wherein a chemical sensitizer such as sulfur, gold or a compound of a metal of Group VIII is used in combination with an additive capable of intensifying the sensitizing effect thereof, and a sensitivity enhancement wherein use is made of an additive capable of exerting a sensitizing effect depending on silver halide emulsion species. Further, a method of conducting a reduction sensitization of silver halide grains has been employed as means for enhancing a photographic sensitivity.
Still further, recently, a sensitizing technology wherein use is made of an organic electron-donating compound having an electron-donating group and a split-off group has been reported (see, for example, U.S. Pat. No. (hereinafter also referred to as U.S. Pat. No.) 5,747,235 and U.S. Pat. No. 5,747,236; European Patent Publication No. (hereinafter also refereed to as EP) 786692A1, EP""s 893731A1 and 893732A1; and U.S. Pat. No. 5,994,051). This is a novel sensitivity-enhancing technology and is effective for sensitivity enhancement.
However, the use of this organic electron-donating compound, although a sensitivity enhancement can be attained, is accompanied by an increase of fog (Dmin). Further, the use of this organic electron-donating compound has a drawback in that the storability would be deteriorated. Therefore, there has been a strong demand for improvement. For overcoming these problems, a joint use with a precursor type antifoggant (see, for example, U.S. Pat. No. 6,472,134B1) and a joint use with a storability improver (see, for example, EP 1227365A1 and Jpn. Pat. Appln. KOKAI No. (hereinafter also referred to as JP-A-) 11-119364 and JP-A-2001-42466) have been studied and improvement thereby has been attempted. However, the attained improvement is still unsatisfactory, and a further improvement is desired.
An object of the present invention is to solve the above problems of the prior art. Specifically, it is an object of the present invention to provide a silver halide photosensitive material of high speed and low fog. That is, the present invention is intended to not only attain a sensitivity enhancement by the use of a novel organic electron-donating compound, of tabular grains of high aspect ratio and large size by the use of a novel organic electron-donating compound but also reduce the fog at fresh and the fog after storage by the use of specific reducing compounds in combination.
The objects of the present invention have been attained by the following means.
(1) A silver halide photosensitive material comprising at least one light sensitive silver halide emulsion layer on a support, wherein the silver halide photosensitive material contains:
at least one compound capable of undergoing a one-electron oxidation to thereby form a one-electron oxidation product thereof, wherein the one-electron oxidation product is capable of releasing further one or more electrons, and
at least one reducing compound having a C/H value of 3 or less, and another reducing compound having a C/H value of more than 3, wherein the C/H value represents a ratio of (the number of Group IV elements)/(the sum of Groups III, V, VI and VII elements).
(2) A silver halide photosensitive material comprising at least one light sensitive silver halide emulsion layer on a support, wherein the silver halide photosensitive material contains:
at least one compound capable of undergoing a one-electron oxidation to thereby form a one-electron oxidation product thereof, wherein the one-electron oxidation product is capable of releasing further one or more electrons, and
at least one reducing compound having a molecular weight of 300 or less, and another reducing compound having a molecular weight of more than 300.
(3) The silver halide photosensitive material according to (1) or (2), wherein the one-electron oxidation product generated by one-electron oxidation, is capable of releasing further two or more electrons.
(4) The silver halide photosensitive material according to any one of (1) to (3), wherein the compound capable of undergoing a one-electron oxidation to thereby form a one-electron oxidation product thereof, wherein the one-electron oxidation product is capable of releasing further one or more electrons, is selected from the following compounds of types 1 to 5:
(Type 1)
A compound capable of undergoing a one-electron oxidation to thereby form a one-electron oxidation product thereof, wherein the one-electron oxidation product is capable of releasing further two or more electrons accompanying a subsequent bond cleavage reaction;
(Type 2)
A compound capable of undergoing a one-electron oxidation to thereby form a one-electron oxidation product thereof, wherein the one-electron oxidation product is capable of releasing further one electron accompanying a subsequent bond cleavage reaction, and the compound has, in its molecule, two or more groups adsorptive to silver halide;
(Type 3)
A compound capable of undergoing a one-electron oxidation to thereby form a one-electron oxidation product thereof, wherein the one-electron oxidation product is capable of releasing further one or more electrons after going through a subsequent bond forming process;
(Type 4)
A compound capable of undergoing a one-electron oxidation to thereby form a one-electron oxidation product thereof, wherein the one-electron oxidation product is capable of releasing further one or more electrons after going through a subsequent intramolecular ring cleavage reaction; and
(Type 5)
A compound having a formula: Xxe2x80x94Y wherein X represents a reducing group, and Y represents a splitting-off group, wherein the reducing group represented by X is capable of undergoing a one-electron oxidation to thereby form a one-electron oxidation product thereof, from which Y is split accompanying a subsequent cleavage reaction of Xxe2x80x94Y bond to thereby form an X radical, the X radical capable of further releasing one electron.
(5) The silver halide photosensitive material according to any one of (1) to (4), wherein the compounds of types 1 to 5 are represented by the following general formula (A), general formula (B), general formula (1), general formula (2), general formula (3), general formula (C), general formula (D), general formula (E), general formula (F) or general formula (G): 
In the general formula (A), RED11 represents a one-electron oxidizable reducing group; L11 represents a split-off group; R112 represents a hydrogen atom or substituent; and R111 represents a nonmetallic atomic group capable of forming, together with carbon atom (C) and RED11, a specific 5- or 6-membered cyclic structure, wherein the 5- or 6-membered cyclic structure means a tetrahydro form, hexahydro form or octahydro form of a 5- or 6-membered aromatic ring (including an aromatic heterocycle).
In the general formula (B), RED12 represents a one-electron oxidizable reducing group; L12 represents a split-off group; each of R121 and R122 represents a hydrogen atom or substituent; and ED12 represents an electron-donating group. In the general formula (B), R121 and RED12, or R121 and R122, or ED12 and RED12 may be bonded with each other to thereby form a cyclic structure.
In the general formula (1), Z1 represents an atomic group capable of forming a 6-membered ring together with the nitrogen atom and the two carbon atoms of the benzene ring; each of R1, R2 and RN1 represents a hydrogen atom or substituent; X1 represents a group capable of substituting on the benzene ring; m1 is an integer of 0 to 3; and L1 represents a split-off group. In the general formula (2), ED21 represents an electron-donating group; each of R11, R12, RN21, R13 and R14 represents a hydrogen atom or substituent; X21 represents a substituent capable of substituting on the benzene ring; m21 is an integer of 0 to 3; and L21 represents a split-off group. Any two of RN21, R13, R14, X21 and ED21 may be bonded with each other to thereby form a cyclic structure. In the general formula (3), each of R32, R33, R31, RN31, Ra and Rb represents a hydrogen atom or substituent; and L31 represents a split-off group. Provided that, when RN31 represents a group other than an aryl group, Ra and Rb are bonded to each other to thereby form an aromatic ring.
In the general formula (C), RED2 has the same meaning as RED12 of the general formula (B); L2 has the same meaning as L11 of the general formula (A), provided that when L2 represents a silyl group the compound represented by the general formula (C) has, in its molecular, a nitrogen-containing heterocycle that is substituted with two or more mercapto groups, as the group adsorptive to silver halide; each of R21 and R22 represents a hydrogen atom or substituent; and RED2 and R21 may be bonded with each other to thereby form a cyclic structure.
In the general formula (D), RED3 represents a one-electron oxidizable reducing group; Y3 represents a reactive moiety that reacts with one electron oxidized RED3. Specifically, Y3 represents an organic group having a carbon-carbon double bond moiety, carbon-carbon triple bond moiety, aromatic moiety or benzo-condensed nonaromatic heterocyclic group. L3 represents a linking group that links between RED3 and Y3.
In the general formulae (E) and (F), each of RED41 and RED42 has the same meaning as RED12 of the general formula (B); and each of R40 to R44 and R45 to R49 represents a hydrogen atom or substituent. In the general formula (F), Z42 represents xe2x80x94CR420R421xe2x80x94, xe2x80x94NR423xe2x80x94 or xe2x80x94Oxe2x80x94. Herein, each of R420 and R421 represents a hydrogen atom or substituent; and R423 represents a hydrogen atom, alkyl group, aryl group or heterocyclic group.
In the general formula (G), RED0 represents a reducing group; L0 represents a splitting-off group; and R0 and R00 each represents a hydrogen atom or substituent. RED0 and R0, or R0 and R00 may be bonded together to form a cyclic structure.
(6) The silver halide photosensitive material according to any one of (1) to (5), wherein the reducing compound is a compound selected from the group consisting of hydroxylamines, hydroxamic acids, hydroxyureas, hydroxyurethanes, hydroxysemicarbazides, reductons (including reducton derivatives), anilines, phenols (including chroman-6-ols, 2,3-dihydrobenzofuran-5-ols, aminophenols, sulfonamidophenols, and polyphenols such as hydroquinones, catechols, resorcinols, benzenetriols and bisphenols), hydrazines, hydrazides, and Phenidons.
(7) The silver halide photosensitive material according to (6), wherein the reducing compound is a compound selected from the group consisting of hydroxylamines represented by the following general formula (B14) and hydroxamic acids represented by the following general formula (B15): 
In the general formula (B14), RN14 represents a hydrogen atom, alkyl group or aryl group, and Z14 represents a nonmetallic atom group capable of forming, together with xe2x80x94Nxe2x95x90Cxe2x80x94, a 5- to 7-membered heterocycle.
In the general formula (B15), Rb15 represents a hydrogen atom, alkyl group, aryl group or heterocycle.
(8) The silver halide photosensitive material according to any one of (1) to (7), wherein the compounds of types 1 to 5 each has, in its molecule, a group adsorptive to silver halide or a partial structure of sensitizing dye.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.
The compound capable of undergoing a one-electron oxidation to thereby form a one-electron oxidation product thereof, wherein the one-electron oxidation product is capable of releasing further one or more electrons, is preferably selected from the following compounds of types 1 to 5:
(Type 1)
A compound capable of undergoing a one-electron oxidation to thereby form a one-electron oxidation product thereof, wherein the one-electron oxidation product is capable of releasing further two or more electrons accompanying a subsequent bond cleavage reaction;
(Type 2)
A compound capable of undergoing a one-electron oxidation to thereby form a one-electron oxidation product thereof, wherein the one-electron oxidation product is capable of releasing further one electron accompanying a subsequent bond cleavage reaction, and the compound has, in its molecule, two or more groups adsorptive to silver halide;
(Type 3)
A compound capable of undergoing a one-electron oxidation to thereby form a one-electron oxidation product thereof, wherein the one-electron oxidation product is capable of releasing further one or more electrons after going through a subsequent bond forming process;
(Type 4)
A compound capable of undergoing a one-electron oxidation to thereby form a one-electron oxidation product thereof, wherein the one-electron oxidation product is capable of releasing further one or more electrons after going through a subsequent intramolecular ring cleavage reaction; and
(Type 5)
A compound having a formula: Xxe2x80x94Y wherein X represents a reducing group, and Y represents a splitting-off group. The compound of type 5 is such a compound that the reducing group represented by X is capable of undergoing a one-electron oxidation to thereby form a one-electron oxidation product thereof, from which Y is split accompanying a subsequent cleavage reaction of Xxe2x80x94Y bond to thereby form an X radical, the X radical capable of further releasing one electron.
Among the compounds of types 1, and 3 to 5, preferable ones are xe2x80x9ccompounds having, in its molecular, an adsorptive group to silver halidexe2x80x9d or xe2x80x9ccompounds having, in its molecular, a partial structure of spectral sensitizing dyexe2x80x9d. More preferable compounds are xe2x80x9ccompounds having, in its molecular, an adsorptive group to silver halidexe2x80x9d.
The compounds of types 1 to 5 will now be described in detail.
With respect to the compound of type 1, the expression xe2x80x9cbond cleavage reactionxe2x80x9d refers to the cleavage of a carbon-carbon bond, carbon-silicon bond, carbon-hydrogen bond, carbon-boron bond, carbon-tin bond, or carbon-germanium bond. Cleavage of carbon-hydrogen bond may further accompany the above bond cleavage. The compound of type 1 is a compound capable of undergoing a one-electron oxidation to thereby form a one-electron oxidation product. The one-electron oxidation product only thereafter capable of undergoing a bond cleavage reaction to thereby further release two or more electrons (preferably three or more electrons).
In another expression, the one-electron oxidation product of the compound of type 1 is capable of being oxidized with further two or more electrons (preferably three or more electrons).
Among the compounds of type 1, preferable compounds are represented by the general formula (A), general formula (B), general formula (1), general formula (2) or general formula (3): 
In the general formula (A), RED11 represents a one-electron oxidizable reducing group; L11 represents a split-off group; R112 represents a hydrogen atom or substituent; and R111 represents a nonmetallic atomic group capable of forming, together with carbon atom (C) and RED11, a specific 5- or 6-membered cyclic structure, wherein the 5- or 6-membered cyclic structure means a tetrahydro form, hexahydro form or octahydro form of a 5- or 6-membered aromatic ring (including an aromatic heterocycle).
In the general formula (B), RED12 represents a one-electron oxidizable reducing group; L12 represents a split-off group; each of R121 and R122 represents a hydrogen atom or substituent; and ED12 represents an electron-donating group. In the general formula (B), R121 and RED12, or R121 and R122, or ED12 and RED12 may be bonded with each other to thereby form a cyclic structure.
These compounds are those which, after a one-electron oxidation of the reducing group represented by RED11 or RED12 of the general formula (A) or general formula (B), can spontaneously split L11 or L12 through a bond cleavage reaction, namely, cleave the C (carbon atom)xe2x80x94toxe2x80x94L11 bond or the C (carbon atom)xe2x80x94toxe2x80x94L12 bond to thereby further release two or more electrons, preferably three or more electrons. 
In the general formula (1), Z1 represents an atomic group capable of forming a 6-membered ring together with the nitrogen atom and the two carbon atoms of the benzene ring; each of R1, R2 and RN1 represents a hydrogen atom or substituent; X1 represents a group capable of substituting on the benzene ring; m1 is an integer of 0 to 3; and L1 represents a split-off group. In the general formula (2), ED21 represents an electron-donating group; each of R11, R12, RN21, R13 and R14 represents a hydrogen atom or substituent; X21 represents a substituent capable of substituting on the benzene ring; m21 is an integer of 0 to 3; and L21 represents a split-off group. Any two of RN21, R13, R14, X21 and ED21 may be bonded with each other to thereby form a cyclic structure. In the general formula (3), each of R32, R33, R31, RN31, Ra and Rb represents a hydrogen atom or substituent; and L31 represents a split-off group. Provided that, when RN31 represents a group other than an aryl group, Ra and Rb are bonded to each other to thereby form an aromatic ring.
These compounds are those which, after a one-electron oxidation, can spontaneously split L1, L21 or L31 through a bond cleavage reaction, namely, cleave the C (carbon atom)xe2x80x94toxe2x80x94L1 bond, the C (carbon atom)xe2x80x94toxe2x80x94L21 bond or the C (carbon atom)xe2x80x94toxe2x80x94L31 bond to thereby further release two or more electrons, preferably three or more electrons.
First, the compound represented by the general formula (A) will be described in detail below.
In the general formula (A), the reducing group represented by RED11 that is capable of being oxidized with one-electron, is a group capable of bonding with R111 described later to thereby form a specific ring. The reducing group can be, for example, a divalent group corresponding to a monovalent group, as mentioned below, having one hydrogen atom removed therefrom at a position that is appropriate for cyclization. The monovalent group can be, for example, any of an alkylamino group, arylamino group (e.g., anilino, naphthylamino), heterocyclic amino group (e.g., benzothiazolylamino, pyrrolylamino), alkylthio group, arylthio group (e.g., phenylthio), heterocyclic thio group, alkoxy group, aryloxy group (e.g., phenoxy), heterocyclic oxy group, aryl group (e.g., phenyl, naphthyl, anthranyl) and aromatic or nonaromatic heterocyclic group (for example, 5- to 7-membered monocyclic or condensed heterocycle containing at least one hetero atom selected from a group consisting of a nitrogen atom, sulfur atom, oxygen atom and selenium atom, which heterocycle can be, for example, a tetrahydroquinoline ring, tetrahydroisoquinoline ring, tetrahydroquinoxaline ring, tetrahydroquinazoline ring, indoline ring, indole ring, indazole ring, carbazole ring, phenoxazine ring, phenothiazine ring, benzothiazoline ring, pyrrole ring, imidazole ring, thiazoline ring, piperidine ring, pyrrolidine ring, morpholine ring, benzimidazole ring, benzimidazoline ring, benzoxazoline ring or methylenedioxyphenyl ring) (hereinafter, for simplicity, RED11 is referred to as denoting a monovalent group). These groups may each have a substituent.
The substituent can be, for example, any of a halogen atom, alkyl groups (including, e.g., an aralkyl group, cycloalkyl group, active methine group), an alkenyl group, alkynyl group, aryl group, heterocyclic group (preferably 5- to 7-membered ring having, as a hetero atom, N, O, S and etc., and the substitution position of the heterocyclic group is not questioned), heterocyclic group containing a quaternated nitrogen atom (e.g., pyridinio, imidazolio, quinolinio or isoquinolinio), acyl group, alkoxycarbonyl group, aryloxycarbonyl group, carbamoyl group, carboxyl group or a salt thereof, sulfonylcarbamoyl group, cacylcarbamoyl group, sulfamoylcarbamoyl group, carbazoyl group, oxalyl group, oxamoyl group, cyano group, carbonimidoyl group, thiocarbamoyl group, hydroxyl group, alkoxy groups (including a group containing ethyleneoxy or propyleneoxy repeating units), aryloxy group, heterocyclic oxy group, acyloxy group, alkoxy- or aryloxy-carbonyloxy group, carbamoyloxy group, sulfonyloxy group, amino group, alkyl-, aryl- or heterocyclic-amino group, acylamino group, sulfonamido group, ureido group, thioureido group, imido group, alkoxy- or aryloxy-carbonylamino group, sulfamoylamino group, semicarbazido group, thiosemicarbazido group, hydrazino group, ammonio group, oxamoylamino group, alkyl- or aryl-sulfonylureido group, acylureido group, acylsulfamoylamino group, nitro group, mercapto group, alkyl-, aryl- or heterocyclic-thio group, alkyl- or aryl-sulfonyl group, alkyl- or aryl-sulfinyl group, sulfo group or a salt thereof, sulfamoyl group, acylsulfamoyl group, sulfonylsulfamoyl group or a salt thereof, and group containing a phosphoramide or phosphoric ester structure. These substituents may be further substituted with these substituents.
In the general formula (A), L11 represents a split-off group that can be split off through a bond cleavage only after a one-electron oxidation of the reducing group represented by RED11. Specifically, L11 represents, for example, a carboxyl group or a salt thereof, silyl group, hydrogen atom, triarylboron anion, trialkylstannyl group, trialkylgermyl group or a group of the formula xe2x80x94CRC1RC2RC3.
When L11 represents a salt of carboxyl group, as a counter ion for forming a salt, there can be mentioned, for example, an alkali metal ion (e.g., Li+, Na+, K+ or Cs+), an alkaline earth metal ion (e.g., Mg2+, Ca2+ or Ba2+), a heavy metal ion (e.g., Ag+ or Fe2+/3+), an ammonium ion or a phosphonium ion. When L11 represents a silyl group, specifically, the silyl group is, for example, a trialkylsilyl group, an aryldialkylsilyl group or a triarylsilyl group. The alkyl of these groups can be, for example, methyl, ethyl, benzyl or t-butyl. The aryl of these groups can be, for example, phenyl.
When L11 represents a triarylboron anion, the aryl thereof is preferably a substituted or unsubstituted phenyl, wherein the substituent can be any of those which may be had by RED11. When L11 represents a trialkylstannyl group or a trialkylgermyl group, the alkyl thereof is a substituted or unsubstituted linear, branched or cyclic alkyl having 1 to 24 carbon atoms, wherein the substituent can be any of those which may be had by RED11.
When L11 represents a group of the formula xe2x80x94CRC1RC2RC3, each of RC1, RC2 and RC3 independently represents any of a hydrogen atom, alkyl group, aryl group, heterocyclic group, alkylthio group, arylthio group, alkylamino group, arylamino group, heterocyclic amino group, alkoxy group, aryloxy group and hydroxyl group. These may be bonded with each other to thereby form a cyclic structure. Each of these may further have a substituent. The substituent can be any of those which may be had by RED11. Provided however that, when one of RC1, RC2 and RC3 represents a hydrogen atom or alkyl group, the remaining two do not represent a hydrogen atom or alkyl group. It is preferred that each of RC1, RC2 and RC3 independently represent an alkyl group, aryl group (especially, phenyl), alkylthio group, arylthio group, alkylamino group, arylamino group, heterocyclic group, alkoxy group or hydroxyl group. Specific examples thereof include methyl, ethyl, cyclohexyl, benzyl, phenyl, p-dimethylaminophenyl, p-methoxyphenyl, 2,4-dimethoxyphenyl, p-hydroxyphenyl, methylthio, phenylthio, phenoxy, methoxy, ethoxy, dimethylamino, N-methylanilino, diphenylamino, morpholino, thiomorpholino and hydroxyl. Examples of groups having a cyclic structure formed by mutual bonding of these include 1,3-dithiolan-2-yl, 1,3-dithian-2-yl, N-methyl-1,3-thiazolidin-2-yl and N-benzylbenzothiazolidin-2-yl.
Preferred groups of the formula xe2x80x94CRC1RC2RC3 can be, for example, trityl, tri(p-hydroxyphenyl)methyl, 1,1-diphenyl-1-(p-dimethylaminophenyl)methyl, 1,1-diphenyl-1-(methylthio)methyl, 1-phenyl-1,1-(dimethylthio)methyl, 1,3-dithiolan-2-yl,2-phenyl-1,3-dithiolan-2-yl, 1,3-dithian-2-yl, 2-phenyl-1,3-dithian-2-yl, 2-methyl-1,3-dithian-2-yl, N-methyl-1,3-thiazolidin-2-yl, 2-methyl-3-methyl-1,3-thiazolidin-2-yl, N-benzylbenzothiazolidin-2-yl, 1,1-diphenyl-1-dimethylaminomethyl and 1,1-diphenyl-1-morpholinomethyl group. It is also preferred that the group of the formula xe2x80x94CRC1RC2RC3 be the same group as the residue resulting from removal of L11 from the general formula (A) as a consequence of selection within the above scopes with respect of the RC1, RC2 and RC3.
In the general formula (A), R112 represents a hydrogen atom or substituent capable of substituting on the carbon atom. When R112 represents a substituent capable of substituting on the carbon atom, the substituent can be, for example, any of those mentioned as substituent examples with respect to the RED11 having a substituent. Provided, however, that R112 and L11 do not represent the same group.
In the general formula (A), R111 represents a group of nonmetallic atoms capable of forming a specific 5-membered or 6-membered cyclic structure together with the carbon atom (C) and RED11. Herein, the expression xe2x80x9cspecific 5-membered or 6-membered cyclic structurexe2x80x9d formed by R111 means a cyclic structure corresponding to a tetrahydro form, hexahydro form or octahydro form of 5-membered or 6-membered aromatic ring (including an aromatic heterocycle). Herein, the terminology xe2x80x9chydro formxe2x80x9d means a cyclic structure resulting from partial hydrogenation of internal carbon to carbon double bonds or carbon to nitrogen double bonds of an aromatic ring (including an aromatic heterocycle). The tetrahydro form refers to a structure resulting from hydrogenation of two carbon to carbon double bonds or carbon to nitrogen double bonds. The hexahydro form refers to a structure resulting from hydrogenation of three carbon to carbon double bonds or carbon to nitrogen double bonds. The octahydro form refers to a structure resulting from hydrogenation of four carbon to carbon double bonds or carbon to nitrogen double bonds. As a result of hydrogenation, the aromatic ring becomes a partially hydrogenated nonaromatic cyclic structure.
Specifically, as examples of 5-membered monocycles, there can be mentioned a pyrrolidine ring, imidazolidine ring, thiazolidine ring, pyrazolidine ring and oxazolidine ring which correspond to tetrahydro forms of aromatic rings including a pyrrole ring, imidazole ring, thiazole ring, pyrazole ring and oxazole ring, respectively. As examples of 6-membered monocycles, there can be mentioned tetrahydro or hexahydro forms of aromatic rings such as a pyridine ring, pyridazine ring, pyrimidine ring and pyrazine ring. Particular examples thereof include a piperidine ring, tetrahydropyridine ring, tetrahydropyrimidine ring and piperazine ring. As examples of 6-membered condensed rings, there can be mentioned a tetralin ring, tetrahydroquinoline ring, tetrahydroisoquinoline ring, tetrahydroquinazoline ring and tetrahydroquinoxaline ring which correspond to tetrahydro forms of aromatic rings including a naphthalene ring, quinoline ring, isoquinoline ring, quinazoline ring and quinoxaline ring, respectively. As examples of tricyclic compounds, there can be mentioned a tetrahydrocarbazole ring, which is a tetrahydro form of a carbazole ring, and an octahydrophenanthridine ring, which is an octahydro form of a phenanthridine ring.
These cyclic structures may further be substituted. As examples of suitable substituents, there can be mentioned those described above with respect to substituents which may be had by the RED11. Substituents of these cyclic structures may be further bonded with each other to thereby form a ring. The thus newly formed ring is a nonaromatic carbon ring or heterocycle.
Preferred range of compounds represented by the general formula (A) of the present invention will be described below.
In the general formula (A), L11 preferably represents a carboxyl group or a salt thereof, or hydrogen atom. More preferably, L11 is a carboxyl group or a salt thereof. As a counter ion of the salt, there can preferably be mentioned an alkali metal ion or an ammonium ion. An alkali metal ion (especially Li+, Na+ or K+ ion) is most preferred.
When L11 represents a hydrogen atom, it is preferred that the compound represented by the general formula (A) have an intramolecular base moiety. By virtue of the action of the base moiety, the compound represented by the general formula (A) is oxidized, and thereafter the hydrogen atom represented by L11 is deprotonized to thereby enable further release of an electron therefrom.
Herein, the base refers to, for example, a conjugated base of acid exhibiting a pKa value of about 1 to about 10. As the base, there can be mentioned, for example, any of nitrogen-containing heterocycles (pyridines, imidazoles, benzimidazoles, thiazoles, etc.), anilines, trialkylamines, an amino group, carbon acids (active methylene anion, etc.), a thioacetate anion, carboxylate (xe2x80x94COOxe2x88x92), sulfate (xe2x80x94SO3xe2x88x92) and an amine oxide ( greater than N+(Oxe2x88x92)xe2x80x94). Preferred base is a conjugated base of acid exhibiting a pKa value of about 1 to about 8. Carboxylate, sulfate and an amine oxide are more preferred. Carboxylate is most preferred. When these bases have an anion, a counter cation may be had thereby. The counter cation can be, for example, an alkali metal ion, an alkaline earth metal ion, a heavy metal ion, an ammonium ion or a phosphonium ion.
These bases are linked at an arbitrary position thereof to the compound represented by the general formula (A). The position at which the base moiety is bonded may be any of RED11, R111 and R112 of the general formula (A). Also, the bases may be linked at substituents of these groups.
When L11 represents a hydrogen atom, it is preferred that the hydrogen atom and the base moiety be linked to each other through an atomic group consisting of 8 or less atoms. More preferably, the linkage is made by an atomic group consisting of 5 to 8 atoms. Herein, what is counted as a linking atomic group refers to an atomic group which links the hydrogen atom to the central atom of base moiety (namely, an atom having an anion, or an atom having a lone electron pair) by a covalent bond. For example, with respect to carboxylate, two atoms of xe2x80x94Cxe2x80x94Oxe2x88x92 are counted. With respect to sulfate, two atoms of Sxe2x80x94Oxe2x88x92 are counted. Also, the carbon atom represented by C in the general formula (A) is included in the count.
In the general formula (A), when L11 represents a hydrogen atom and when RED11 represents an aniline whose nitrogen atom forms a 6-membered monocyclic saturated ring structure (for example, a piperidine ring, piperazine ring, morpholine ring, thiomorpholine ring or selenomorpholine ring) together with R111, it is preferred that the compound have an adsorptive group acting on silver halides in its molecule. It is more preferred that the compound simultaneously have an intramolecular base moiety, the base moiety and the hydrogen atom linked to each other through an atomic group consisting of 8 or less atoms.
In the general formula (A), it is preferred that RED11 represents an alkylamino group, arylamino group, heterocyclic amino group, aryl group, or aromatic or nonaromatic heterocyclic group. As the heterocyclic group, preferred group is, for example, tetrahydroquinolinyl, tetrahydroquinoxalinyl, tetrahydroquinazolinyl, indolyl, indolenyl, carbazolyl, phenoxazinyl, phenothiazinyl, benzothiazolinyl, pyrrolyl, imidazolyl, thiazolidinyl, benzimidazolyl, benzimidazolinyl or 3,4-methylenedioxyphenyl-1-yl. More preferred group is an arylamino group (especially an anilino) or aryl group (especially an phenyl). When RED11 represents an aryl group, it is preferred that the aryl group has at least one electron-donating group (the number of electron-donating groups is preferably 4 or less, more preferably 1 to 3). Herein, the electron-donating group specifically refers to a hydroxyl group, alkoxy group, mercapto group, sulfonamido group, acylamino group, alkylamino group, arylamino group, heterocyclic amino group, active methine group, electron-excessive aromatic heterocyclic group (e.g., indolyl, pyrrolyl, imidazolyl, benzimidazolyl, thiazolyl, benzthiazolyl or indazolyl), or a nonaromatic nitrogen-containing heterocyclic group that is bonded to the carbon atom of the general formula (A) via its nitrogen atom (e.g., pyrrolidinyl, indolinyl, piperidinyl, piperazinyl or morpholino). Herein, the active methine group refers to a methine group substituted with two electron-withdrawing groups. Herein, the electron-withdrawing groups refer to an acyl group, alkoxycarbonyl group, aryloxycarbonyl group, carbamoyl group, alkylsulfonyl group, arylsulfonyl group, sulfamoyl group, trifluoromethyl group, cyano group, nitro group and carbonimidoyl group. These two electron-withdrawing groups may be bonded with each other to thereby form a circular structure. When RED11 represents an aryl group, the substituent of the aryl group is preferably an alkylamino group, hydroxyl group, alkoxy group, mercapto group, sulfonamido group, active methine group, or nonaromatic nitrogen-containing heterocyclic group that is bonded to the carbon atom of the general formula (A) via its nitrogen atom. More preferably, the substituent is an alkylamino group, hydroxyl group, active methine group, or nonaromatic nitrogen-containing heterocyclic group that is bonded to the carbon atom of the general formula (A) via its nitrogen atom. Most preferably, the substituent is an alkylamino group, or nonaromatic nitrogen-containing heterocyclic group that is bonded to the carbon atom of the general formula (A) via its nitrogen atom.
In the general formula (A), R112 preferably represents any of a hydrogen atom, alkyl group, aryl group (e.g., phenyl), alkoxy group (e.g., methoxy, ethoxy or benzyloxy), hydroxyl group, alkylthio group (e.g., methylthio or butylthio), amino group, alkylamino group, arylamino group and heterocyclic amino group. More preferably, R112 represents any of a hydrogen atom, alkyl group, alkoxy group, phenyl group, or alkylamino group.
In the general formula (A), R111 preferably represents a group of nonmetallic atoms capable of forming the following specific 5-membered or 6-membered cyclic structure together with the carbon atom (C) and RED11. Specifically, the cyclic structure formed by R111 may be, for example, either of a pyrrolidine ring and an imidazolidine ring which correspond to tetrahydro forms of monocyclic 5-membered aromatic rings including a pyrrole ring and imidazole ring, respectively. Also, the cyclic structure may be a tetrahydro or hexahydro form of monocyclic 6-membered aromatic ring such as a pyridine ring, pyridazine ring, pyrimidine ring or pyrazine ring. For example, the cyclic structure may be a piperidine ring, tetrahydropyridine ring, tetrahydropyrimidine ring or piperazine ring. Further, the cyclic structure may be any of a tetralin ring, tetrahydroquinoline ring, tetrahydroisoquinoline ring, tetrahydroquinazoline ring and tetrahydroquinoxaline ring which correspond to tetrahydro forms of condensed-ring of 6-membered aromatic rings including a naphthalene ring, a quinoline ring, isoquinoline ring, quinazoline ring and quinoxaline ring, respectively. Still further, the cyclic structure may be a tetrahydrocarbazole ring which is a tetrahydro form of a tricyclic aromatic carbazole ring, or octahydrophenanthridine ring which is an octahydro form of a phenanthridine ring. The cyclic structure formed by R111 is more preferably selected from a pyrrolidine ring, imidazolidine ring, piperidine ring, tetrahydropyridine ring, tetrahydropyrimidine ring, piperazine ring, tetrahydroquinoline ring, tetrahydroquinazoline ring, tetrahydroquinoxaline ring and tetrahydrocarbazole ring. Most preferably, the cyclic structure formed by R111 is selected from a pyrrolidine ring, piperidine ring, piperazine ring, tetrahydroquinoline ring, tetrahydroquinazoline ring, tetrahydroquinoxaline ring and tetrahydrocarbazole ring. Optimally, the cyclic structure formed by R111 is selected from a pyrrolidine ring, piperidine ring and tetrahydroquinoline ring.
Now, the general formula (B) will be described in detail.
With respect to the RED12 and L12 of the general formula (B), not only the meanings but also the preferred ranges thereof are the same as those of the RED11 and L11 of the general formula (A), respectively. Provided, however, that RED12 represents a monovalent group unless the following cyclic structure is formed thereby. For example, the monovalent group can be any of those mentioned with respect to RED11. With respect to R121 and R122, not only the meanings but also the preferred ranges thereof are the same as those of the R112 of the general formula (A). ED12 represents an electron-donating group. R121 and RED12; R121 and R122; or ED12 and RED12 may be bonded with each other to thereby form a cyclic structure.
In the general formula (B), the electron-donating group represented by ED12 refers to a hydroxyl group, alkoxy group, mercapto group, alkylthio group, arylthio group, heterocyclic thio group, sulfonamido group, acylamino group, alkylamino group, arylamino group, heterocyclic amino group, active methine group, electron-excessive aromatic heterocyclic group (e.g., indolyl, pyrrolyl or indazolyl), a nonaromatic nitrogen-containing heterocyclic group that is bonded to the carbon atom of the general formula (B) via its nitrogen atom (e.g., pyrrolidinyl, piperidinyl, indolinyl, piperazinyl or morpholino), or an aryl group substituted with any of these electron-donating groups (e.g., p-hydroxyphenyl, p-dialkylaminophenyl, an o,p-dialkoxyphenyl or 4-hydroxynaphthyl). Herein, the active methine group is the same as described above as a substituent when RED11 represents an aryl group. ED12 preferably represents a hydroxyl group, alkoxy group, mercapto group, sulfonamido group, alkylamino group, arylamino group, active methine group, electron-excessive aromatic heterocyclic group, nonaromatic nitrogen-containing heterocyclic group that is bonded to the carbon atom of the general formula (B) via its nitrogen atom, or phenyl group substituted with any of these electron-donating groups. More preferably, ED12 represents a hydroxyl group, mercapto group, sulfonamido group, alkylamino group, arylamino group, active methine group, nonaromatic nitrogen-containing heterocyclic group that is bonded to the carbon atom of the general formula (B) via its nitrogen atom, or phenyl group substituted with any of these electron-donating groups (e.g., p-hydroxyphenyl, p-dialkylaminophenyl or o,p-dialkoxyphenyl).
In the general formula (B), R121 and RED12; R122 and R121; or ED12 and RED12 may be bonded with each other to thereby form a cyclic structure. The thus formed cyclic structure is a substituted or unsubstituted cyclic structure of a 5- to 7-membered monocyclic or condensed-ring nonaromatic carbon ring or heterocycle. When R121 and RED12 form a cyclic structure, the thus formed cyclic structure can be, for example, a pyrrolidine ring, pyrroline ring, imidazolidine ring, imidazoline ring, thiazolidine ring, thiazoline ring, pyrazolidine ring, pyrazoline ring, oxazolidine ring,. oxazoline ring, indane ring, piperidine ring, piperazine ring, morpholine ring, tetrahydropyridine ring, tetrahydropyrimidine ring, indoline ring, tetralin ring, tetrahydroquinoline ring, tetrahydroisoquinoline ring, tetrahydroquinoxaline ring, tetrahydro-1,4-oxazine ring, 2,3-dihydrobenzo-1,4-oxazine ring, tetrahydro-1,4-thiazine ring, 2,3-dihydrobenzo-1,4-thiazine ring, 2,3-dihydrobenzofuran ring or 2,3-dihydrobenzothiophene ring. When ED12 and RED12 form a cyclic structure, ED12 preferably represents an amino group, alkylamino group or arylamino group. The cyclic structure formed thereby can be, for example, a tetrahydropyrazine ring, piperazine ring, tetrahydroquinoxaline ring or tetrahydroisoquinoline ring. When R122 and R121 form a cyclic structure, the thus formed cyclic structure can be, for example, a cyclohexane ring or cyclopentane ring.
Those which are more preferred among the compounds of the general formula (A) of the present invention are represented by the following general formulae (10) to (12). Those which are more preferred among the compounds of the general formula (B) are represented by the following general formulae (13) and (14): 
With respect to the L100, L101, L102, L103 and L104 of the general formulae (10) to (14), not only the meanings but also the preferred ranges thereof are the same as those of the L11 of the general formula (A).
With respect to R1100 and R1101; R1110 and R1111; R1120 and R1121; R1130 and R1131; and R1140 and R1141; not only the meanings but also the preferred ranges thereof are the same as those of the R122 and R121, respectively of the general formula (B). With respect to the ED13 and ED14, not only the meanings but also the preferred ranges thereof are the same as those of the ED12 of the general formula (B). Each of X10, X11, X12, X13 and X14 represents a substituent capable of substituting on the benzene ring. Each of m10, m11, m12, m13 and m14 is an integer of 0 to 3. When it is 2 or more, a plurality of X10, X11, X12, X13 or X14 groups may be the same or different. Each of Y12 and Y14 represents an amino group, alkylamino group, arylamino group, nonaromatic nitrogen-containing heterocyclic group that is bonded to the benzene ring of the general formula (12) or (14) via its nitrogen atom (e.g., pyrrolyl, piperidinyl, indolinyl, piperazino or morpholino), hydroxyl group or alkoxy group.
Each of Z10, Z11 and Z12 represents a nonmetallic atomic group capable of forming a specific cyclic structure. The specific cyclic structure formed by Z10 means a cyclic structure corresponding to a tetrahydro form or hexahydro form of 5- or 6-membered, monocyclic or condensed-ring, nitrogen-containing aromatic heterocycle. As such a cyclic structure, there can be mentioned, for example, a pyrrolidine ring, imidazolidine ring, thiazolidine ring, pyrazolidine ring, piperidine ring, tetrahydropyridine ring, tetrahydropyrimidine ring, piperazine ring, tetrahydroquinoline ring, tetrahydroisoquinoline ring, tetrahydroquinazoline ring or tetrahydroquinoxaline ring. The specific cyclic structure formed by Z11 refers to a tetrahydroquinoline ring or tetrahydroquinoxaline ring. The specific cyclic structure formed by Z12 refers to a tetralin ring, tetrahydroquinoline ring or tetrahydroisoquinoline ring.
Each of RN11 and RN13 represents a hydrogen atom or substituent capable of substituting on the nitrogen atom. The substituent can be, for example, any of an alkyl group, alkenyl group, alkynyl group, aryl group, heterocyclic group and acyl group, preferably an alkyl group or aryl group.
The substituents capable of substituting on the benzene ring, represented by X10, X11, X12, X13 or X14, can be, for example, those which may be had by the RED11 of the general formula (A). Preferably, the substituents can be a halogen atom, alkyl group, aryl group, heterocyclic group, acyl group, alkoxycarbonyl group, aryloxycarbonyl group, carbamoyl group, cyano group, alkoxy group (including a group containing ethyleneoxy or propyleneoxy repeating units), alkyl-, aryl- or heterocyclic-amino group, an acylamino group, sulfonamido group, ureido group, thioureido group, imido group, alkoxy- or aryloxy-carbonylamino group, nitro group, alkyl-, aryl- or heterocyclic-thio group, alkyl- or aryl-sulfonyl group, a sulfamoyl group, etc. Each of m10, m11, m12, m13 and m14 is preferably an integer of 0 to 2, more preferably 0 or 1.
Each of Y12 and Y14 preferably represents an alkylamino group, arylamino group, nonaromatic nitrogen-containing heterocyclic group that is bonded to the benzene ring of the general formula (12) or (14) via its nitrogen atom, hydroxyl group or alkoxy group. More preferably, each of Y12 and Y14 represents an alkylamino group, 5- or 6-membered nonaromatic nitrogen-containing heterocyclic group that is bonded to the benzene ring of the general formula (12) or (14) via its nitrogen atom, or hydroxyl group. Most preferably, each of Y12 and Y14 represents an alkylamino group (especially, dialkylamino) or a 5- or 6-membered nonaromatic nitrogen-containing heterocyclic group that is bonded to the benzene ring of the general formula (12) or (14) via its nitrogen atom.
In the general formula (13), R1131 and X13; R1131 and RN13; R1130 and X13; or R1130 and RN13 may be bonded with each other to thereby form a cyclic structure. In the general formula (14), R1141 and X14; or R1141 and R1140; ED14 and X14; or R1140 and X14 may be bonded with each other to thereby form a cyclic structure. The thus formed cyclic structure is a substituted or unsubstituted cyclic structure consisting of a 5- to 7-membered monocyclic or condensed-ring nonaromatic carbon ring or heterocycle. When, in the general formula (13), R1131 and X13 are bonded with each other to thereby form a cyclic structure, or R1131 and RN13 are bonded with each other to thereby form a cyclic structure, the resultant compound, like that wherein no cyclic structure is formed, is a preferred Example of the compounds of the general formula (13). As the cyclic structure formed by R1131 and X13 in the general formula (13), there can be mentioned, for example, any of an indoline ring, in which case, R1131 represents a single bond, tetrahydroquinoline ring, tetrahydroquinoxaline ring, 2,3-dihydrobenzo-1,4-oxazine ring and 2,3-dihydrobenzo-1,4-thiazine ring. Of these, an indoline ring, tetrahydroquinoline ring and tetrahydroquinoxaline ring are especially preferred. As the cyclic structure formed by R1131 and RN13 in the general formula (13), there can be mentioned, for example, any of a pyrrolidine ring, pyrroline ring, imidazolidine ring, imidazoline ring, thiazolidine ring, thiazoline ring, pyrazolidine ring, pyrazoline ring, oxazolidine ring, oxazoline ring, piperidine ring, piperazine ring, morpholine ring, tetrahydropyridine ring, tetrahydropyrimidine ring, indoline ring, tetrahydroquinoline ring, tetrahydroisoquinoline ring, tetrahydroquinoxaline ring, tetrahydro-1,4-oxazine ring, 2,3-dihydrobenzo-1,4-oxazine ring, tetrahydro-1,4-thiazine ring, 2,3-dihydrobenzo-1,4-thiazine ring, 2,3-dihydrobenzofuran ring and 2,3-dihydrobenzothiophene ring of these, a pyrrolidine ring, piperidine ring, tetrahydroquinoline ring and tetrahydroquinoxaline ring are especially preferred.
When, in the general formula (14), R1141 and X14 are bonded with each other to thereby form a cyclic structure, or ED14 and X14 are bonded with each other to thereby form a cyclic structure, the resultant compound, like that wherein no cyclic structure is formed, is a preferred Example of the compounds of the general formula (14). As the cyclic structure formed by the bonding of R1141 and X14 in the general formula (14), there can be mentioned, for example, an indane ring, tetralin ring, tetrahydroquinoline ring, tetrahydroisoquinoline ring or indoline ring. As the cyclic structure formed by the bonding of ED14 and X14, there can be mentioned, for example, a tetrahydroisoquinoline ring or tetrahydrocinnoline ring.
Now, the general formulae (1) to (3) will be described.
In the general formulae (1) to (3), each of R1, R2, R11, R12 and R31 independently represents a hydrogen atom or substituent. With respect to these, not only the meanings but also the preferred ranges thereof are the same as those of the R112 of the general formula (A). Each of L1, L21 and L31 independently represents a split-off group, which can be any of those mentioned as examples in the above description of the L11 of the general formula (A). The preferred ranges thereof are also the same as mentioned there. Each of X1 and X21 represents a substituent capable of substituting on the benzene ring. Each thereof independently represents any of those mentioned as the substituent examples with respect to substituted RED11 of the general formula (A). Each of m1 and m21 is an integer of 0 to 3, preferably 0 to 2, and more preferably 0 or 1.
Each of RN1, RN21 and RN31 represents a hydrogen atom or substituent capable of substituting on the nitrogen atom. The substituent can preferably be any of an alkyl group, aryl group and heterocyclic group. These groups may further have a substituent. This substituent can be any of those which may be had by the RED11 of the general formula (A). Each of RN1, RN21 and RN31 preferably represents a hydrogen atom, alkyl group or aryl group, more preferably a hydrogen atom or alkyl group.
Each of R13, R14, R32, R33, Ra and Rb independently represents a hydrogen atom or substituent capable of substituting on the carbon atom. The substituent can be any of those that may be had by the RED11 of the general formula (A). The substituent can preferably be, for example, an alkyl group, aryl group, acyl group, alkoxycarbonyl group, carbamoyl group, cyano group, alkoxy group, acylamino group, sulfonamido group, ureido group, thioureido group, alkylthio group, arylthio group, alkylsulfonyl group, arylsulfonyl group or sulfamoyl group.
In the general formula (1), Z1 represents an atomic group capable of forming a 6-membered ring together with the nitrogen atom and the two carbon atoms of the benzene ring. The 6-membered ring formed with Z1 is a nonaromatic carbon ring or heterocycle condensed with the benzene ring of the general formula (1). Specifically, the atomic group can be any of a tetrahydroquinoline ring, tetrahydroquinoxaline ring and tetrahydroquinazoline ring, which ring structures include the benzene ring to which the atomic group condensed. These may have a substituent. The substituent can be any of those mentioned as examples when the R112 of the general formula (A) represents a substituent, and the preferred range thereof is also the same as mentioned there.
In the general formula (1), Z1 preferably represents an atomic group capable of forming a tetrahydroquinoline ring or tetrahydroquinoxaline ring together with the nitrogen atom and the two carbon atoms of the benzene ring.
In the general formula (2), ED21 represents an electron-donating group. With respect to the ED21, not only the meaning but also the preferred range thereof is the same as those of the ED12 of the general formula (B).
In the general formula (2), any two of RN21, R13, R14, X21 and ED21 may be bonded with each other to thereby form a cyclic structure. The cyclic structure formed by RN21 and X21 is preferably a 5- to 7-membered nonaromatic carbon ring or heterocycle condensed with the benzene ring of the general formula (2). For example, it can be a tetrahydroquinoline ring, tetrahydroquinoxaline ring, indoline ring or 2,3-dihydro-5,6-benzo-1,4-thiazine ring. Preferably, it is a tetrahydroquinoline ring, tetrahydroquinoxaline ring or indoline ring.
In the general formula (3), when RN31 represents a group other than aryl group, Ra and Rb are bonded with each other to thereby form an aromatic ring. Herein, this aromatic ring is an aryl group. Herein, the aromatic group is an aryl group (e.g., phenyl or naphthyl) or an aromatic heterocyclic group (e.g., a pyridine ring, pyrrole ring, quinoline ring or indole ring). An aryl group is preferred. The aromatic ring group may have a substituent. The substituent can be any of those mentioned when X1 of the general formula (1) represents a substituent, and the preferred range thereof is also the same as mentioned there.
In the general formula (3), it is preferred that Ra and Rb be bonded with each other to thereby form an aromatic ring (especially a phenyl group).
In the general formula (3), R32 preferably represents, for example, a hydrogen atom, alkyl group, aryl group, hydroxyl group, alkoxy group, mercapto group or amino group. When R32 represents a hydroxyl group, it is a preferred mode that simultaneously R33 represents an electron-withdrawing group. This electron-withdrawing group refers to any of an acyl group, alkoxycarbonyl group, aryloxycarbonyl group, carbamoyl group, alkylsulfonyl group, arylsulfonyl group, sulfamoyl group, trifluoromethyl group, cyano group, nitro group and carbonimidoyl group. Of these, an acyl group, alkoxycarbonyl group, carbamoyl group and cyano group are preferred.
The compound of type 2 will be described below.
The compound of type 2 is a compound capable of undergoing a one-electron oxidation to thereby form a one-electron oxidation product and capable of, only thereafter, undergoing a bond cleavage reaction to thereby further release another electron. That is, the one-electron oxidation product of the compound of type 2 is capable of being oxidized with a further one-electron oxidation. Herein, the expression xe2x80x9cbond cleavage reactionxe2x80x9d refers to the cleavage of a carbon-carbon bond, carbon-silicon bond, carbon-hydrogen bond, carbon-boron bond, carbon-tin bond, or carbon-germanium bond. Cleavage of carbon-hydrogen bond may accompany the above bond cleavage.
Provided that the compound of type 2 has, in its molecule, two or more (preferably two to six, more preferably two to four) groups adsorptive to silver halide. More preferably, the compound of type 2 has a nitrogen-containing heterocyclic group substituted with two or more mercapto groups, as its adsorptive group.
Among the compounds of type 2, those preferred are represented by general formula (C): 
Herein, the compound of the general formula (C) is, after the one-electron oxidation of the reducing group represented by RED2, L2 is spontaneously split off through a bond cleavage reaction, namely, the C (carbon atom)xe2x80x94toxe2x80x94L2 bond is cleaved, so that further another electron can be released.
With respect to RED2 of the general formula (C), not only the meaning but also the preferred range thereof is the same as those of the RED12 of the general formula (B). L2 has the same meaning as described for L11 of the general formula (A). The preferable range of L2 is also the same as that of L11. When L2 represents a silyl group, the compound of the general formula (C) has, in its molecule, a nitrogen-containing heterocyclic group that is substituted by two or more mercapto groups, as an adsorptive group. Each of R21 and R22 represents a hydrogen atom or substituent. With respect to these, not only the meanings but also the preferred ranges thereof are the same as those of the R112 of the general formula (A). RED2 and R21 may be bonded with each other to thereby form a cyclic structure.
The thus formed cyclic structure is preferably a 5- to 7-membered monocyclic or condensed-ring nonaromatic carbon ring or heterocycle, which may have a substituent. Provided however that the cyclic structure is not one corresponding to a tetrahydro form, hexahydro form or octahydro form of an aromatic ring or aromatic heterocycle. The substituent can be any of those mentioned as substituent examples with respect to substituted RED11 of the general formula (A). The cyclic structure is preferably a cyclic structure corresponding to a dihydro form of an aromatic or nonaromatic heterocycle. Preferable Example of the cyclic structure, for example, is a 2-pyrroline ring, 2-imidazoline ring, 2-thiazoline ring, 1,2-dihydropyridine ring, 1,4-dihydropyridine ring, indoline ring, benzimidazoline ring, benzothiazoline ring, benzoxazoline ring, 2,3-dihydrobenzothiophene ring, 2,3-dihydrobenzofuran ring, benzo-xcex1-pyran ring, 1,2-dihydroquinoline ring, 1,2-dihydroquinazoline ring and 1,2-dihydroquinoxaline ring.
Of these, a 2-imidazoline ring, 2-thiazoline ring, indoline ring, benzimidazoline ring, benzothiazoline ring, benzoxazoline ring, 1,2-dihydropyridine ring, 1,2-dihydroquinoline ring, 1,2-dihydroquinazoline ring and 1,2-dihydroquinoxaline ring are preferred. An indoline ring, benzimidazoline ring, benzothiazoline ring and 1,2-dihydroquinoline ring are more preferred. An indoline ring is most preferred.
The compound of type 3 will be described below.
The compound of type 3 is a compound characterized in that it can undergo a one-electron oxidation to thereby form a one-electron oxidation product, the one-electron oxidation product being capable of releasing further one or more electrons after going through a subsequent bond-forming process. The bond-forming process refers to the formation of bond between atoms, for example, of carbon-carbon bond, carbon-nitrogen bond, carbon-sulfur bond or carbon-oxygen bond.
The compound of type 3 is preferably a compound characterized in that it can undergo a one-electron oxidation to thereby form a one-electron oxidation product, the one-electron oxidation product subsequently reacting with a reactive group moiety (a carbon to carbon double bond moiety, a carbon to carbon triple bond moiety, an aromatic group moiety or a benzo-condensed nonaromatic heterocyclic group moiety) which coexists in the molecule to thereby form a bond, followed by further release of one or more electrons.
The one-electron oxidation product formed by the one-electron oxidation of the compound of type 3 refers to a cation radical species, which may undergo splitting of a proton to thereby form a neutral radical species. This one-electron oxidation product (cation radical species or neutral radical species) reacts with a carbon to carbon double bond moiety, a carbon to carbon triple bond moiety, an aromatic group moiety and a benzo-condensed nonaromatic heterocyclic group moiety which coexists in the molecule, thereby forming interatomic bonds such as carbon-carbon bond, carbon-nitrogen bond, carbon-sulfur bond and carbon-oxygen bond. Thus, a new intramolecular cyclic structure is formed. Simultaneously or thereafter, further one or more electrons are released. The characteristic of the compound of type 3 resides in this respect.
More specifically, the compound of type 3 is characterized in that the bond-forming reaction after the one-electron oxidation leads to formation of a new radical species of cyclic structure, from which the second electron is further released directly or through splitting of a proton to thereby cause an oxidation thereof.
Furthermore, the compounds of type 3 include one exhibiting such a capability that the thus formed two-electron oxidation product subsequently undergoes a tautomeric reaction accompanying a transfer of proton either by way of a hydrolytic reaction or directly to thereby further release one or more, generally two or more, electrons, resulting in an oxidation thereof. Still further, the compounds of type 3 include one exhibiting such a capability that, without undergoing such a tautomeric reaction, further one or more, generally two or more, electrons are directly released from the two-electron oxidation product, resulting in oxidation thereof.
The compound of type 3 is preferably represented by the general formula (D):
RED3xe2x80x94L3xe2x80x94Y3xe2x80x83xe2x80x83(D)
In the general formula (D), RED3 represents a one-electron oxidizable reducing group, Y3 represents a reactive moiety that reacts with one electron oxidized RED3 after RED3 is one-electron oxidized. Specifically, Y3 represents an organic group having a carbon-carbon double bond moiety, carbon-carbon triple bond moiety, aromatic moiety or benzo-condensed nonaromatic heterocyclic group. L3 represents a linking group that links between RED3 and Y3.
In the general formula (D), RED3 preferably represents an arylamino group, heterocyclic amino group, aryloxy group, arylthio group, aryl group, or aromatic or nonaromatic heterocyclic group (especially preferably a nitrogen-containing heterocyclic group). More preferably, RED3 represents an arylamino group, heterocyclic amino group, aryl group, or aromatic or nonaromatic heterocyclic group. With respect to the heterocyclic group, it is preferred to use, for example, a tetrahydroquinoline ring group, tetrahydroquinoxaline ring group, tetrahydroquinazoline ring group, indoline ring group, indole ring group, carbazole ring group, phenoxazine ring group, phenothiazine ring group, benzothiazoline ring group, pyrrole ring group, imidazole ring group, thiazole ring group, benzimidazole ring group, benzimidazoline ring group, benzothiazoline ring group or 3,4-methylenedioxyphenyl-1-yl ring group.
An arylamino group (especially anilino), an aryl group (especially phenyl) or an aromatic or nonaromatic heterocyclic group is most preferred as RED3.
When RED3 represents an aryl group, it is preferred that the aryl group has at least one electron-donating group. Herein, the electron-donating group specifically refers to a hydroxyl group, alkoxy group, mercapto group, alkylthio group, sulfonamido group, acylamino group, alkylamino group, arylamino group, heterocyclic amino group, active methine group, electron-excessive aromatic heterocyclic group (e.g., indolyl, pyrrolyl or indazolyl), or a nonaromatic nitrogen-containing heterocyclic group that is bonded to L3 via its nitrogen atom (e.g., pyrrolidinyl, indolinyl, piperidinyl, piperazinyl, morpholino or thiomorpholino). Herein, the active methine group refers to a methine group substituted with two electron-withdrawing groups. Herein, the electron-withdrawing groups refer to an acyl group, alkoxycarbonyl group, aryloxycarbonyl group, carbamoyl group, alkylsulfonyl group, arylsulfonyl group, sulfamoyl group, trifluoromethyl group, cyano group, nitro group and carbonimidoyl group. These two electron-withdrawing groups may be bonded with each other to thereby form a cyclic structure.
When RED3 represents an aryl group, the substituent of the aryl group is preferably an alkylamino group, hydroxyl group, alkoxy group, mercapto group, sulfonamido group, active methine group, or nonaromatic nitrogen-containing heterocyclic group that is bonded to L3 via its nitrogen atom. More preferably, the substituent is an alkylamino group, hydroxyl group, active methine group, or nonaromatic nitrogen-containing heterocyclic group that is bonded to L3 via its nitrogen atom. Most preferably, the substituent is an alkylamino group, or nonaromatic nitrogen-containing heterocyclic group that is bonded to L3 via its nitrogen atom.
When the reactive group represented by Y3 is an organic substituted group having a carbon to carbon double bond or a carbon to carbon triple bond moiety, the substituent of the substituted organic group can preferably be any of, for example, an alkyl group (preferably having 1 to 8 carbon atoms), aryl group (preferably having 6 to 12 carbon atoms), alkoxycarbonyl group (preferably having 2 to 8 carbon atoms), carbamoyl group, acyl group and electron-donating group. Herein, the electron-donating group refers to any of an alkoxy group (preferably having 1 to 8 carbon atoms), hydroxyl group, amino group, alkylamino group (preferably having 1 to 8 carbon atoms), arylamino group (preferably having 6 to 12 carbon atoms), heterocyclic amino group (preferably having 2 to 6 carbon atoms), sulfonamido group, acylamino group, active methine group, mercapto group, an alkylthio group (preferably having 1 to 8 carbon atoms), arylthio group (preferably having 6 to 12 carbon atoms) and aryl group having any of these groups as a substituent (the number of carbon atoms of the aryl moiety is preferably in the range of 6 to 12). The hydroxyl group may be protected with a silyl group, for example, a trimethylsilyloxy group, t-butyldimethylsilyloxy group, triphenylsilyloxy group, triethylsilyloxy group or phenyldimethylsilyloxy group. Examples of the carbon to carbon double bond moiety and carbon to carbon triple bond moiety are vinyl group and ethynyl group, respectively.
When Y3 represents an organic group comprising a carbon to carbon double bond moiety having a substituent, the substituent thereof is more preferably, for example, an alkyl group, phenyl group, acyl group, cyano group, alkoxycarbonyl group, carbamoyl group or electron-donating group. Herein, the electron-donating group preferably refers to any of an alkoxy group, hydroxyl group, which may be protected with a silyl group, amino group, alkylamino group, arylamino group, sulfonamido group, active methine group, mercapto group, alkylthio group and phenyl group having any of these electron-donating groups as a substituent, among the substituents mentioned above.
When the carbon to carbon double bond moiety has a hydroxyl group as a substituent, Y3 contains a partial structure of the formula  greater than C1xe2x95x90C2(xe2x80x94OH)xe2x80x94. This may be tautomerized into a partial structure of the formula  greater than C1Hxe2x80x94C2(xe2x95x90O)xe2x80x94. Further, in this structure, it is preferred that the substituent on C1 carbon be an electron-withdrawing group. In this instance, Y3 has a partial structure of xe2x80x9cactive methylene groupxe2x80x9d or xe2x80x9cactive methine groupxe2x80x9d. The electron-withdrawing groups capable of providing this partial structure of active methylene group or active methine group are the same as mentioned in the above description of xe2x80x9cactive methine groupsxe2x80x9d.
When Y3 represents an organic group having a carbon to carbon triple bond moiety having a substituent, the substituent is preferably, for example, an alkyl group, phenyl group, alkoxycarbonyl group, carbamoyl group or electron-donating group. Herein, the electron-donating group preferably refers to any of an alkoxy group, amino group, alkylamino group, arylamino group, heterocyclic amino group, sulfonamido group, acylamino group, active methine group, mercapto group, alkylthio group and phenyl group having any of these electron-donating groups as a substituent.
When Y3 represents an organic group having an aromatic group moiety, the aromatic group is preferably an indole ring group or an aryl group (especially preferably a phenyl group) having an electron-donating group as a substituent. Herein, the electron-donating group preferably refers to a hydroxyl group (the hydroxyl group may be protected with a silyl group), alkoxy group, amino group, alkylamino group, active methine group, sulfonamido group or mercapto group.
When Y3 represents a benzo-condensed organic group having a nonaromatic heterocyclic group, the benzo-condensed nonaromatic heterocyclic group is preferably one having an aniline structure as an internal partial structure, which can be, for example, an indoline ring group, 1,2,3,4-tetrahydroquinoline ring group, 1,2,3,4-tetrahydroquinoxaline ring group or 4-quinolone ring group.
In the general formula (D), the reactive group represented by Y3 is more preferably an organic group containing a carbon to carbon double bond moiety, aromatic group moiety or benzo-condensed nonaromatic heterocyclic group. Still more preferably, the reactive group is an organic group having a carbon to carbon double bond moiety, phenyl group having an electron-donating group as a substituent, indole ring group, or benzo-condensed nonaromatic heterocyclic group having an aniline structure as an internal partial structure. Herein, it is more preferred that the carbon to carbon double bond moiety have at least one electron-donating group as a substituent.
When the reactive group represented by Y3 of the general formula (D) has the same partial structure as that of the reducing group represented by RED3 of the general formula (D) as a result of selection within the range described hereinbefore, also, preferred examples of the compounds of the general formula (D) are provided thereby.
In the general formula (D), L3 represents a linking group which links between RED3 and Y3. For example, L3 represents a group consisting of each of, or each of combinations of, a single bond, alkylene group, arylene group, heterocyclic group, xe2x80x94Oxe2x80x94, xe2x80x94Sxe2x80x94, xe2x80x94NRNxe2x80x94, xe2x80x94C(xe2x95x90O)xe2x80x94, xe2x80x94SO2xe2x80x94, xe2x80x94SOxe2x80x94 and xe2x80x94P(xe2x95x90O)xe2x80x94. Herein, RN represents a hydrogen atom, alkyl group, aryl group or heterocyclic group. The linking group represented by L3 may have a substituent. The substituent can be any of those mentioned hereinbefore as substituents which may be had by RED11 of the general formula (A). The linking group represented by L3 can engage in linkage by replacing one arbitrary hydrogen atom of each of the groups represented by RED3 and L3 at an arbitrary position thereof.
The linking group represented by L3 of the general formula (D) is preferably such that, when the cationic radical species (X30 .) formed as a result of oxidation of RED3 of the general formula (D) or radical species (X.) formed through splitting of proton therefrom reacts with the reactive group represented by Y3 of the general formula (D) to thereby form a bond, the relevant atomic groups engaging therein can form a 3- to 7-membered cyclic structure including L3. From this viewpoint, it is preferred that the radical species (X30 . or X.), the reactive group represented by Y3 and the group L3 be linked to each other by a group of 3 to 7 atoms.
As a preferred Example of L3, there can be mentioned a divalent linking group selected from a single bond, alkylene group (especially methylene, ethylene or propylene), an arylene group (especially phenylene), xe2x80x94C(xe2x95x90O)xe2x80x94 group, xe2x80x94Oxe2x80x94 group, xe2x80x94NHxe2x80x94 group, xe2x80x94N(alkyl group)xe2x80x94 group and combinations thereof.
Among the compounds of the general formula (D), preferred compounds are represented by the following general formulae (D-1) to (D-4): 
In the general formulae (D-1) to (D-4), each of A100, A200 and A400 represents an arylene group or divalent heterocyclic group, and A300 represents an aryl group or a heterocyclic group. The preferred range thereof is the same as that of RED3 of the general formula (D). Each of L301, L302, L303 and L304 represents a linking group. With respect to these, not only the meanings but also the preferred ranges thereof are the same as those of L3 of the general formula (D). Each of Y100, Y200, Y300 and Y400 represents a reactive group. With respect to these, not only the meanings but also the preferred ranges thereof are the same as those of Y3 of the general formula (D). Each of R3100, R3110, R3200, R3210 and R3310 represents a hydrogen atom or substituent. Each of R3100 and R3110 preferably represents a hydrogen atom, alkyl group or aryl group. Each of R3200 and R3310 preferably represents a hydrogen atom. R3210 preferably represents a substituent. This substituent is preferably an alkyl group or aryl group. R3110 and A100; R3210 and A200; and R3310 and A300 may be bonded with each other to thereby form a cyclic structure. The thus formed cyclic structure is preferably, for example, a tetralin ring, indane ring, tetrahydroquinoline ring or indoline ring. X400 represents a hydroxyl group, mercapto group or alkylthio group, preferably represents a hydroxyl group or mercapto group, and more preferably represents a mercapto group.
Among the compounds of the general formulae (D-1) to (D-4), the compounds of the general formulae (D-2), (D-3) and (D-4) are preferred. The compounds of the general formulae (D-2) and (D-3) are more preferred.
The compound of type 4 will be described below.
The compound of type 4 is a compound having a circular structure substituted with a reducing group, which compound can undergo a one-electron oxidation of the reducing group and thereafter a cleavage reaction of the circular structure to thereby further release one or more electrons.
In the compound of type 4, the cyclic structure is cleaved after a one-electron oxidation. Herein, the cyclic cleavage reaction refers to the following scheme of reaction: 
In the formulae, the compound a represents a compound of type 4. In the compound a, D represents a reducing group, and X and Y represent atoms forming a bond of the circular structure which is cleaved after a one-electron oxidation. First, the compound a undergoes a one-electron oxidation to thereby form a one-electron oxidation product b. Then, the Dxe2x80x94X single bond is converted to a double bond, and simultaneously the Xxe2x80x94Y bond is cleaved to thereby form an open-ring product c. An alternative route wherein a proton is split from the one-electron oxidation product b to thereby form a radical intermediate d, from which an open-ring product e is similarly formed, may be taken. One or more electrons are further released from the thus formed open-ring product c or e. The characteristic of this compound of the present invention resides in this respect.
The cyclic structure of the compound of type 4 refers to a nonaromatic, saturated or unsaturated, monocyclic or condensed-ring, 3- to 7-membered carbon ring or heterocycle. A saturated cyclic structure is preferred, and a 3- or 4-membered ring is more preferred. As preferred cyclic structures, there can be mentioned a cyclopropane ring, cyclobutane ring, oxirane ring, oxetane ring, aziridine ring, azetidine ring, episulfide ring and thietane ring. Of these, a cyclopropane ring, cyclobutane ring, oxirane ring, oxetane ring and azetidine ring are preferred. A cyclopropane ring, cyclobutane ring and azetidine ring are more preferred. The cyclic structure may have a substituent.
The compound of type 4 is preferably represented by the general formula (E) or (F): 
With respect to RED41 and RED42 of the general formulae (E) and (F), not only the meanings but also the preferred ranges thereof are the same as those of RED12 of the general formula (B). Each of R40 to R44 and R45 to R49 represents a hydrogen atom or substituent. The substituent can be any of those which may be had by RED12. In the general formula (F), Z42 represents xe2x80x94CR42OR421xe2x80x94, xe2x80x94NR423xe2x80x94 or xe2x80x94Oxe2x80x94. Each of R420 and R421 represents a hydrogen atom or substituent, and R423 represents a hydrogen atom, alkyl group, aryl group or heterocyclic group.
In the general formula (E), R40 preferably represents any of a hydrogen atom, alkyl group, alkenyl group, alkynyl group, aryl group, heterocyclic group, alkoxy group, amino group, alkylamino group, arylamino group, heterocyclic amino group, alkoxycarbonyl group, acyl group, carbamoyl group, cyano group and sulfamoyl group. Of these, a hydrogen atom, alkyl group, aryl group, heterocyclic group, alkoxy group, alkoxycarbonyl group, acyl group and carbamoyl group are more preferred. A hydrogen atom, alkyl group, aryl group, heterocyclic group, alkoxycarbonyl group and carbamoyl group are most preferred.
With respect to R41 to R44, it is preferred that a case wherein at least one thereof be a donating group. It is also preferred that a case wherein R41 and R42; or R43 and R44 be simultaneously electron-withdrawing groups. More preferably, at least one of R41 to R44 is a donating group. Most preferably, at least one of R41 to R44 is a donating group while, a group(s) that is not a donating group among R41 to R44, is (are) a hydrogen atom or alkyl group. The electron-withdrawing groups are the same as those mentioned in the above description of active methine group.
Herein, the donating group refers to a hydroxyl group, alkoxy group, aryloxy group, mercapto group, acylamino group, sulfonylamino group, active methine group, or group selected from preferred examples of the RED41 and RED42 groups. As the donating group, there can preferably be used any of an alkylamino group, arylamino group, heterocyclic amino group, 5-membered aromatic heterocyclic group having one nitrogen atom in its ring (the 5-membered aromatic ring may be monocyclic or in the form of condensed rings), a nonaromatic nitrogen-containing heterocyclic group that is bonded to the carbon atom of the general formula (E) via its nitrogen atom and phenyl group substituted with at least one electron-donating group, wherein the electron-donating group refers to a hydroxyl group, alkoxy group, aryloxy group, amino group, alkylamino group, arylamino group, heterocyclic amino group or nonaromatic nitrogen-containing heterocyclic group that is bonded to the carbon atom of the phenyl group via its nitrogen atom). Of these, an alkylamino group, arylamino group, 5-membered aromatic heterocyclic group having one nitrogen atom in its ring, wherein the aromatic heterocycle refers to an indole ring, pyrrole ring or carbazole ring, and a phenyl group substituted with at least one electron-donating group, in particular, a phenyl group substituted with three or more alkoxy groups or a phenyl group substituted with a hydroxyl group, alkylamino group or arylamino group, are more preferred. An arylamino group, 5-membered aromatic heterocyclic group having one nitrogen atom in its ring, wherein the 5-membered aromatic heterocyclic group represents a 3-indolyl group, and a phenyl group substituted with at least one electron-donating group, in particular, a trialkoxyphenyl group or a phenyl group substituted with an alkylamino group or arylamino group, are most preferred.
In the general formula (F), the preferred range of R45 is the same as described above with respect to R40 of the general formula (E). Each of R46 to R49 preferably represents any of a hydrogen atom, alkyl group, alkenyl group, alkynyl group, aryl group, heterocyclic group, hydroxyl group, alkoxy group, amino group, alkylamino group, arylamino group, heterocyclic amino group, mercapto group, arylthio group, alkylthio group, acylamino group and sulfonamino group. Of these, a hydrogen atom, alkyl group, aryl group, heterocyclic group, alkoxy group, alkylamino group, arylamino group and heterocyclic amino group are more preferred. Most preferably, each of R46 to R49 represents a hydrogen atom, alkyl group, aryl group, heterocyclic group, alkylamino group or arylamino group when Z42 represents a group of the formula xe2x80x94CR420R421xe2x80x94; represents a hydrogen atom, alkyl group, aryl group or heterocyclic group when Z42 represents a xe2x80x94NR423xe2x80x94; and represents a hydrogen atom, alkyl group, aryl group or heterocyclic group when Z42 represents xe2x80x94Oxe2x80x94.
Z42 preferably represents xe2x80x94CR42OR421xe2x80x94 or xe2x80x94NR423xe2x80x94, and more preferably represents xe2x80x94NR423xe2x80x94. Each of R420 and R421 preferably represents any of a hydrogen atom, alkyl group, alkenyl group, alkynyl group, aryl group, heterocyclic group, hydroxyl group, alkoxy group, amino group, mercapto group, acylamino group and sulfonamino group. Of these, a hydrogen atom, alkyl group, aryl group, heterocyclic group, alkoxy group and amino group are more preferred. R423 preferably represents a hydrogen atom, alkyl group, aryl group or aromatic heterocyclic group, and more preferably represents methyl, ethyl, isopropyl, t-butyl, t-amyl, benzyl, diphenylmethyl, allyl, phenyl, naphthyl, 2-pyridyl, 4-pyridyl or 2-thiazolyl.
When each of R40 to R49, R420, R421 and R423 represents a substituent, the total number of carbon atoms of each thereof is preferably 40 or less, more preferably 30 or less, and most preferably 15 or less. These substituents may be bonded with each other or bonded with other moieties (e.g., RED41, RED42 or Z42) of the molecule to thereby form rings.
It is preferred that the compounds of types 1, 3 and 4 according to the present invention be xe2x80x9ccompounds each having, in its molecule, a group adsorptive to silver halidesxe2x80x9d or xe2x80x9ccompounds each having, in its molecule, a partial structure of spectral sensitizing dyexe2x80x9d. More preferably, the compounds of types 1, 3 and 4 according to the present invention are xe2x80x9ccompounds each having, in its molecule, a group adsorptive to silver halidesxe2x80x9d. The compound of type 2 is a xe2x80x9ccompound having, in its molecule, two or more groups adsorptive to silver halidesxe2x80x9d. The compounds of types 1 to 4 are more preferably xe2x80x9ccompounds each having a nitrogen-containing heterocyclic group substituted with two or more mercapto groups as an adsorptive groupxe2x80x9d.
With respect to the compounds of types 1 to 4 according to the present invention, the adsorptive group to silver halides refers to a group directly adsorbed onto silver halides or a group capable of promoting the adsorption onto silver halides. For example, the adsorptive group is a mercapto group (or a salt thereof), thione group (xe2x80x94C(xe2x95x90S)xe2x80x94), heterocyclic group containing at least one atom selected from a nitrogen atom, sulfur atom, selenium atom and tellurium atom, sulfido group, cationic group or ethynyl group. Provided however that, with respect to the compound of type 2 according to the present invention, a sulfido group is not included in the adsorptive groups thereof.
The terminology xe2x80x9cmercapto group (or a salt thereof)xe2x80x9d as the adsorptive group means not only a mercapto group (or a salt thereof) per se but also, preferably, a heterocyclic, aryl or alkyl group substituted with at least one mercapto group (or a salt thereof). Herein, the heterocyclic group refers to a 5- to 7-membered, monocyclic or condensed-ring, aromatic or nonaromatic heterocycle. As the heterocyclic group, there can be mentioned, for example, an imidazole ring group, thiazole ring group, oxazole ring group, benzimidazole ring group, benzothiazole ring group, benzoxazole ring group, triazole ring group, thiadiazole ring group, oxadiazole ring group, tetrazole ring group, purine ring group, pyridine ring group, quinoline ring group, isoquinoline ring group, pyrimidine ring group or triazine ring group. The heterocyclic group may be one containing a quaternary nitrogen atom, which may become a mesoion as a result of dissociation of a substituted mercapto group. This heterocyclic group can be, for example, any of an imidazolium ring group, pyrazolium ring group, thiazolium ring group, triazolium ring group, tetrazolium ring group, thiadiazolium ring group, pyridinium ring group, pyrimidinium ring group and triazinium ring group. Of these groups, a triazolium ring group (e.g., 1,2,4-triazolium-3-thiolate ring group) is preferred. The aryl group can be, for example, a phenyl group or naphthyl group. The alkyl group can be a linear, or branched, or cyclic alkyl group having 1 to 30 carbon atoms. When the mercapto group forms a salt, as the counter ion, there can be mentioned, for example, a cation of alkali metal, alkaline earth metal or heavy metal (e.g., Li+, Na+, K+, Mg2+, Ag+ or Zn2+), an ammonium ion, a heterocyclic group containing a quaternary nitrogen atom, or a phosphonium ion.
The mercapto group as the adsorptive group may further be tautomerized into a thione group. As such, there can be mentioned, for example, a thioamido group (herein a xe2x80x94C(xe2x95x90S)xe2x80x94NHxe2x80x94 group) or a group containing a partial structure of the thioamido group, namely, a linear or cyclic thioamido group, thioureido group, thiourethane group or dithiocarbamic acid ester group. As examples of suitable cyclic groups, there can be mentioned, for example, a thiazolidine-2-thione group, oxazolidine-2-thione group, 2-thiohydantoin group, rhodanine group, isorhodanine group, thiobarbituric acid group and 2-thioxo-oxazolidin-4-one group.
The thione groups as the adsorptive group include not only the above thione groups resulting from tautomerization of mercapto groups but also a linear or cyclic thioamido group, thioureido group, thiourethane group and dithiocarbamic acid ester group which cannot be tautomerized into mercapto groups, i.e., not having any hydrogen atom at the xcex1-position of thione group.
The heterocyclic group containing at least one atom selected from a nitrogen atom, sulfur atom, selenium atom and tellurium atom as the adsorptive group is a nitrogen-containing heterocyclic group having an xe2x80x94NHxe2x80x94 group capable of forming an iminosilver ( greater than NAg) as a partial structure of the heterocycle, or a heterocyclic group having an xe2x80x9cxe2x80x94Sxe2x80x94xe2x80x9d group or xe2x80x9cxe2x80x94Sexe2x80x94xe2x80x9d group or xe2x80x9cxe2x80x94Texe2x80x94xe2x80x9d group or xe2x80x9cxe2x95x90Nxe2x80x94xe2x80x9d group capable of coordinating to silver ion by coordinate bond as a partial structure of the heterocycle. The former heterocyclic group can be, for example, a benzotriazole group, triazole group, indazole group, pyrazole group, tetrazole group, benzimidazole group, imidazole group or purine group. The latter heterocyclic group can be, for example, a thiophene group, thiazole group, oxazole group, benzothiazole group, benzoxazole group, thiadiazole group, oxadiazole group, triazine group, selenoazole group, benzoselenoazole group, tellurazole group or benzotellurazole group. The former heterocyclic group is preferred.
As the sulfido group as the adsorptive group, there can be mentioned all the groups having a partial structure of xe2x80x9cxe2x80x94Sxe2x80x94xe2x80x9d. Preferably, the sulfido group is a group having a partial structure of alkyl (or alkylene)-S-alkyl (or alkylene), aryl (or arylene)-S-alkyl (or alkylene), or aryl (or arylene)-S-aryl (or arylene). This sulfido group may be in the form of a cyclic structure or xe2x80x94Sxe2x80x94Sxe2x80x94 group. As examples of sulfido groups forming a cyclic structure, there can be mentioned groups containing a thiolane ring, 1,3-dithiolane ring, 1,2-dithiolane ring, thiane ring, dithiane ring, tetrahydro-1,4-thiazine ring (thiomorpholine ring) or the like. Among the sulfido groups, groups having a partial structure of alkyl (or alkylene)-S-alkyl (or alkylene) are especially preferred.
The cationic group as the adsorptive group refers to a group containing a quaternary nitrogen atom. For example, it is a group containing an ammonio group or a nitrogen-containing heterocyclic group containing a quaternary nitrogen atom. However, the cationic group does not become part of an atomic group forming a dye structure (for example, cyanine chromophore). Herein, the ammonio group is, for example, a trialkylammonio group, dialkylarylammonio group or alkyldiarylammonio group. For example, as such, there can be mentioned benzyldimethylammonio group, trihexylammonio group or phenyldiethylammonio group. The nitrogen-containing heterocyclic group containing a quaternary nitrogen atom can be, for example, any of pyridinio group, quinolinio group, isoquinolinio group and imidazolio group. Of these, pyridinio group and imidazolio group are preferred. A pyridinio group is most preferred. The nitrogen-containing heterocyclic group containing a quaternary nitrogen atom may have an arbitrary substituent. However, when the nitrogen-containing heterocyclic group is a pyridinio group or imidazolio group, the substituent is preferably selected from, for example, an alkyl group, aryl group, acylamino group, chlorine atom, alkoxycarbonyl group and carbamoyl group. When the nitrogen-containing heterocyclic group is a pyridinio group, the substituent is most preferably a phenyl group.
The ethynyl group as the adsorptive group refers to a xe2x80x94Cxe2x89xa1CH group, whose hydrogen atom may be replaced by a substituent.
The above adsorptive groups may have an arbitrary substituent.
Furthermore, examples of suitable adsorptive groups include those listed on pages 4 to 7 of JP-A-11-95355, (U.S. Pat. No. 6,054,260, the entire contents of which is incorporated herein by reference).
In the present invention, it is preferred that the adsorptive group be a nitrogen-containing heterocyclic group substituted with mercapto (e.g., a 2-mercaptothiadiazole group, 3-mercapto-1,2,4-triazole group, 5-mercaptotetrazole group, 2-mercapto-1,3,4-oxadiazole group, 2-mercaptobenzoxazole group, 2-mercaptobenzothiazole group or 1,5-dimethyl-1,2,4-triazolium-3-thiolate group), or a nitrogen-containing heterocyclic group having an xe2x80x94NHxe2x80x94 group capable of forming an iminosilver ( greater than NAg) as a partial structure of the heterocycle (e.g., a benzotriazole group, benzimidazole group or indazole group). More preferably, the adsorptive group is a 5-mercaptotetrazole group, 3-mercapto-1,2,4-triazole group or benzotriazole group. Most preferably, the adsorptive group is a 3-mercapto-1,2,4-triazole group or 5-mercaptotetrazole group.
Among the compounds of the present invention, those having, in its molecule, two or more mercapto groups as partial structures are also especially preferred. Herein, the mercapto group (xe2x80x94SH) may become a thione group when it can be tautomerized. Examples of such compounds may include a compound possessing in its molecule two or more adsorptive groups having the above mercapto group or thione group as a partial structure (e.g., a ring forming thioamido group, alkylmercapto group, arylmercapto group or heterocyclic mercapto group), and a compound possessing at least one adsorptive group having, in the adsorptive group per se, two or more mercapto groups or thione groups as a partial structure (e.g., a dimercapto-substituted nitrogen-containing heterocyclic group).
As examples of adsorptive groups having two or more mercapto groups as a partial structure (e.g., dimercapto-substituted nitrogen-containing heterocyclic groups), there can be mentioned a 2,4-dimercaptopyrimidine group, 2,4-dimercaptotriazine group, 3,5-dimercapto-1,2,4-triazole group, 2,5-dimercapto-1,3-thiazole group, 2,5-dimercapto-1,3-oxazole group, 2,7-dimercapto-5-methyl-s-triazolo[1,5-a]pyrimidine group, 2,6,8-trimercaptopurine group, 6,8-dimercaptopurine group, 3,5,7-trimercapto-s-triazolotriazine group, 4,6-dimercaptopyrazolopyrimidine group and 2,5-dimercaptoimidazole group. Of these, a 2,4-dimercaptopyrimidine group, 2,4-dimercaptotriazine group and 3,5-dimercapto-1,2,4-triazole group are especially preferred.
Although substitution with the adsorptive group may be effected at any position of the general formulae (A) to (F) and general formulae (1) to (3), it is preferred that the substitution be effected at RED11, RED12, RED2 and RED3 in the general formulae (A) to (D); at RED41, R41, RED42 and R46 to R48 in the general formulae (E) and (F); and at any arbitrary position except R1, R2, R11, R12, R31, L1, L21 and L31 in the general formulae (1) to (3). It is more preferred that, in all the general formulae (A) to (F), the substitution be effected at RED2 to RED42.
The partial structure of spectral sensitizing dye refers to a group containing a chromophore of spectral sensitizing dye, and refers to a residue resulting from removal of an arbitrary hydrogen atom or substituent from a spectral sensitizing dye compound. Although substitution with the partial structure of spectral sensitizing dye may be effected at any position of the general formulae (A) to (F) and general formulae (1) to (3), it is preferred that the substitution be effected at RED11, RED12, RED2 and RED3 in the general formulae (A) to (D); at RED41, R41, RED42 and R46 to R48 in the general formulae (E) and (F); and at any arbitrary position except R1, R2, R11, R12, R31, L1, L21 and L31 in the general formulae (1) to (3). It is more preferred that, in all the general formulae (A) to (F), the substitution be effected at RED2 to RED42. Preferred spectral sensitizing dyes are those typically employed in color sensitization techniques, which include, for example, cyanine dyes, composite cyanine dyes, merocyanine dyes, composite merocyanine dyes, homopolar cyanine dyes, styryl dyes and hemicyanine dyes. Representative spectral sensitizing dyes are disclosed in Research Disclosure, item 36544, September 1994, the entire contents of which are incorporated herein by reference. These spectral sensitizing dyes can be synthesized by persons skilled in the art to which the invention pertains in accordance with the procedure described in the above Research Disclosure or F. M. Hamer xe2x80x9cThe Cyanine Dyes and Related Compoundsxe2x80x9d, Interscience Publishers, New York, 1964. Further, all the dyes described on pages 7 to 14 of JP-A-11-95355 (U.S. Pat. No. 6,054,260, entire contents of which are incorporated herein by reference) per se are applicable.
With respect to the compounds of types 1 to 4 according to the present invention, the total number of carbon atoms is preferably in the range of 10 to 60, more preferably 10 to 50, most preferably 11 to 40, and optimally 12 to 30.
With respect to the compounds of types 1 to 4 according to the present invention, a one-electron oxidation thereof is induced upon exposure of the silver halide photographic photosensitive material using the compounds. After the subsequent reaction, another electron, or two or more electrons depending on the type of compound are released to thereby cause further oxidation. The oxidation potential with respect to the first electron is preferably about 1.4 V or below, more preferably 1.0 V or below. This oxidation potential is preferably higher than 0 V, more preferably higher than 0.3 V. Thus, the oxidation potential is preferably in the range of about 0 to about 1.4 V, more preferably about 0.3 to about 1.0 V.
Herein, the oxidation potential can be measured in accordance with the cyclic voltammetry technique. For example, a sample compound is dissolved in a solution consisting of a 80%:20% (vol. %) mixture of acetonitrile and water (containing 0.1 M lithium perchlorate), and nitrogen gas is passed through the solution for 10 min. Thereafter, the oxidation potential is measured at 25xc2x0 C. and at a potential scanning rate of 0.1 V/sec with the use of a glassy carbon disk as a working electrode, a platinum wire as a counter electrode and a calomel electrode (SCE) as a reference electrode. The oxidation potential vs. SCE is determined at the peak potential of cyclic voltammetry wave.
With respect to, among the compounds of types 1 to 4 according to the present invention, those which undergo a one-electron oxidation and, after a subsequent reaction, further release another electron, the oxidation potential at the latter stage is preferably in the range of xe2x88x920.5 to xe2x88x922 V, more preferably xe2x88x920.7 to xe2x88x922 V, and most preferably xe2x88x920.9 to xe2x88x921.6 V.
With respect to, among the compounds of types 1 to 4 according to the present invention, those which undergo a one-electron oxidation and, after a subsequent reaction, further release two or more electrons to thereby effect oxidation, the oxidation potential at the latter stage is not particularly limited. The reason is that the oxidation potential with respect to the second electron cannot be clearly distinguished from the oxidation potential with respect to the third electron et seqq., so that it is often difficult to practically accomplish accurate measuring and distinguishing thereof.
Specific examples of the compounds of types 1 to 4 according to the present invention will be listed below, which however in no way limit the scope of the present invention. 
The compounds of types 1 to 4 according to the present invention are the same as those described in detail in Japanese Patent Applications Nos. 2001-272137, 2002-188536, 2002-188537 and 2002-192373, the entire contents of the specification of the patent applications of which are incorporated herein by references. The specific compounds disclosed in the specifications of these patent applications can also be mentioned as specific examples of the compounds of types 1 to 4 according to the present invention. Further, examples of synthesis of the compounds of types 1 to 4 according to the present invention are also the same as those described in these patent applications.
The compound of type 5 will be described below.
The compound of type 5 is represented by Xxe2x80x94Y, wherein X represents a reducing group and Y represents a split-off group. The compound of type 5 is such a compound that the reducing group represented by X is capable of undergoing a one-electron oxidation to thereby form a one-electron oxidation product thereof, from which Y is split accompanying a subsequent cleavage reaction of Xxe2x80x94Y bond to thereby form an X radical, the X radical capable of further releasing another electron. The reaction when such compound as type 5 is oxidized may be represented by the following formulae: 
The oxidation potential of the compound of type 5 is preferably in the range of 0 to 1.4 V, more preferably 0.3 to 1.0 V. The oxidation potential of the radical X. formed according to the above reaction formula is preferably in the range of xe2x88x920.7 to xe2x88x922.0 V, more preferably xe2x88x920.9 to xe2x88x921.6 V.
The compound of type 5 is preferably represented by the general formula (G): 
In the general formula (G), RED0 represents a reducing group. L0 represents a split-off group, and each of R0 and R00 represents a hydrogen atom or substituent. RED0 and R0, and also R0 and R00 may be bonded with each other to thereby form a ring structure. RED0 represents the same groups as those represented by RED2 of the general formula (C), and the preferred ranges thereof are also the same. R0 and R00 respectively represent the same groups as those represented by R21 and R22 of the general formula (C), and the preferred ranges thereof are also the same. Provided however that each of R0 and R00 does not represent the same groups as those represented by L0, except for a hydrogen atom. RED0 and R0 may be bonded with each other to thereby form a ring structure. This ring structure can be, for example, any of those formed by bonding between RED2 and R21 of the general formula (C), and the preferred ranges thereof are also the same. Examples of the ring structures formed by bonding between R0 and R00 include a cyclopentane ring and a tetrahydrofuran ring. L0 of the general formula (G) represents the same groups as those represented by L2 of the general formula (C), and the preferred ranges thereof are also the same.
Each of the compounds of the general formula (G), although preferably having, in its molecule, an adsorptive group to silver halides or a partial structure of spectral sensitizing dye, does not simultaneously have two or more adsorptive groups in its molecule when L0 represents a group other than a silyl group. Provided however that with respect to the sulfide group as an adsorptive group, two or more thereof may be had, irrespective of L0.
The adsorptive groups to silver halides possessed by the compounds of the general formula (G) can be, for example, those which may be had by the compounds of types 1 to 4 according to the present invention. Furthermore, the adsorptive groups include a selenoxo group (xe2x80x94Cxe2x95x90Sexe2x80x94), a telluroxo group (xe2x80x94Cxe2x95x90Texe2x80x94), a seleno group (xe2x80x94Sexe2x80x94), a telluro group (xe2x80x94Texe2x80x94) and an active methine group. Herein, the selenoxo group (xe2x80x94Cxe2x95x90Sexe2x80x94) and telluroxo group (xe2x80x94Cxe2x95x90Texe2x80x94) respectively refer to Se and Te derivatives of a compound having a thione group (xe2x80x94Cxe2x95x90Sxe2x80x94) and, as mentioned above with respect to thione groups, may be groups containing a selenoamido group (xe2x80x94Cxe2x95x90Sexe2x80x94NHxe2x80x94) and a telluramido group (xe2x80x94Cxe2x95x90Texe2x80x94NHxe2x80x94), respectively. The seleno group (xe2x80x94Sexe2x80x94) and telluro group (xe2x80x94Texe2x80x94) also respectively refer to Se and Te derivatives of a compound having a sulfido group (xe2x80x94Sxe2x80x94), and can be, for example, any of Se and Te substitution products of compounds having a sulfido group. The active methine group refers to a methine group substituted with two electron-withdrawing groups. Herein, the electron withdrawing group refers to an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, a carbamoyl group, an alkylsulfonyl group, an arylsulfonyl group, a sulfamoyl group, a trifluoromethyl group, a cyano group, a nitro group or a carbonimidoyl group. The above two electron-withdrawing groups may be bonded with each other to thereby form a ring structure.
The adsorptive groups possessed by the compounds of the general formula (G) are preferably a mercapto group (or its salt), a thione group (xe2x80x94Cxe2x95x90Sxe2x80x94), a heterocyclic group containing at least one atom selected from a nitrogen atom, sulfur atom, selenium atom and tellurium atom, and a sulfido group. More preferably, the adsorptive groups are a nitrogen-containing heterocyclic group substituted with mercapto, and a nitrogen-containing heterocyclic group having a xe2x80x94NHxe2x80x94 group capable of forming iminosilver ( greater than NAg) as a partial structure of the heterocycle.
These are the same as those described with respect to the preferred range of adsorptive groups which may be possessed by the compounds of types 1 to 4. Although the site of adsorptive group substitution in the general formula (G) is not limited, the substitution is preferably effected at RED0 or R0, more preferably RED0.
The partial structure of spectral sensitizing dye which may be had by the compounds of the general formula (G) is the same as the partial structure of spectral sensitizing dye which may be had by the compounds of types 1 to 4 according to the present invention.
Specific examples of the compounds of the general formula (G) will be set out below, to which however the present invention is in no way limited. 
Specific examples of the compounds of the general formula (G) further include examples of compounds described as xe2x80x9cone photon two electrons sensitizersxe2x80x9d or xe2x80x9cdeprotonating electron-donating sensitizersxe2x80x9d in the patent publications and specifications of, for example, JP-A-9-211769 (compounds PMT-1 to S-37 listed in Tables E and F on pages 28 to 32), JP-A-9-211774, JP-A-11-95355 (compounds INV 1 to 36), Japanese Patent Application KOHYO Publication 2001-500996 (compounds 1 to 74, 80 to 87 and 92 to 122), U.S. Pat. Nos. 5,747,235 and 5,747,236, EP 786692A1 (compounds INV 1 to 35), EP 893732A1 and U.S. Pat. Nos. 6,054,260 and 5,994,051, the entire contents of which are incorporated herein by reference.
The compound of types 1 to 5 may be used at any time during emulsion preparation or in photosensitive material manufacturing step, for example, during grain formation, at desalting step, at the time of chemical sensitization, or before coating. The compound may be added separately in a plurality of times during the steps. Preferable addition timing is from the completion of grain formation to before a desalting step, at the time of chemical sensitization (immediately before the initiation of chemical sensitization to immediately after the completion thereof), or before coating. More preferable addition timing is at chemical sensitization or before coating.
The compound of types 1 to 5 according to the present invention may preferably be added by dissolving it to a water or water-soluble solvent such as methanol, ethanol or a mixture of solvents. When the compound is added to water, if the solubility of the compound increases in a case where pH is raised or lowered, the compound may be added to the solvent by raising or lowering the pH thereof.
It is preferable that the compound of types 1 to 5 according to the present invention is used in an emulsion layer, but the compound may be added in a protective layer or interlayer together with the emulsion layer, thereby making the compound diffuse during coating. The addition time of the compound of the invention is irrespective of before or after the addition time of a sensitizing dye. Each of the compounds is preferably contained in a silver halide emulsion layer in an amount of 1xc3x9710xe2x88x929 to 5xc3x9710xe2x88x922 mol, more preferably 1xc3x9710xe2x88x928 to 2xc3x9710xe2x88x923 mol pre mol of silver halide.
Next, the reducing compounds according to the present invention will now be described.
The term xe2x80x9creducing compoundxe2x80x9d in the present invention indicates a compound selected from hydroxylamines, hydroxamic acids, hydroxyureas, hydroxyurethanes, hydroxysemicarbazides, reductons (including reducton derivatives), anilines, phenols (including chroman-6-ols, 2,3-dihydrobenzofuran-5-ols, aminophenols, sulfonamidophenols, and polyphenols such as hydroquinones, catechols, resorcinols, benzenetriols and bisphenols), hydrazines, hydrazides, and Phenidons.
Hydroxylamines are compounds preferably represented by general formula (B1), hydroxamic acids are compounds preferably represented by general formula (B2), hydroxyureas are compounds preferably represented by general formula (B3), hydroxyurethanes are compounds preferably represented by general formula (B4), hydroxysemicarbazides are compounds preferably represented by general formula (B5), reductons are compounds preferably represented by general formula (B6), anilines are compounds preferably represented by general formula (B7), phenols are compounds preferably represented by general formulae (B8), (B9) and (B10), hydrazines are compounds preferably represented by general formula (B11), hydrazides are compounds preferably represented by general formula (B12), and Phenidons are compounds preferably represented by general formula (B13): 
In the general formulae (B1) to (B13), each of Rb1, Rb2, Rb3, Rb4, Rb5, Rb70, Rb71, Rb110, Rb111, Rb112, Rb113, Rb12, Rb13, RN1, RN2, RN3, RN4, and RN5 represents a hydrogen atom, alkyl group, aryl group, or heterocyclic group, each of RH3, RH5, Rxe2x80x2H5, RH12, Rxe2x80x2H12, and RH13 represents a hydrogen atom, alkyl group, aryl group, acyl group, alkylsulfonyl group or arylsulfonyl group, and among them RH3 may further represent a hydroxy group. Each of Rb100, Rb101, Rb102, and Rb130 to Rb133 represents a hydrogen atom or a substituent. Each of Y7 and Y8 represents a substituent excluding a hydroxy group, Y9 represents a substituent, m7 represents an integer of 0 to 5, m8 represents an integer of 1 to 5, and mg represents an integer of 0 to 4. If m7, m8 and m9 represent 2 or greater, each pair of two adjacent Y7""s, Y8""s and Y9""s may bind to each other to form an aryl group condensed to the benzene ring (for example, a benzene-condensed ring), and it may further have a substituent. Z10 represents a nonmetallic atomic group which can form a ring, and X12 represents a hydrogen atom, alkyl group, aryl group, heterocyclic group, alkoxy group, amino group (including alkylamino group, arylamino group, heterocyclic amino group, and cyclic amino group), or carbamoyl group.
In the general formula (B6), each of X6 and Xxe2x80x26 represents a hydroxy group, alkoxy group, mercapto group, alkylthio group, amino group (including an alkylamino group, arylamino group, heterocyclic amino group, and a cyclic amino group), acylamino group, sulfonamido group, alkoxycarbonylamino group, ureido group, acyloxy group, acylthio group, alkylaminocarbonyloxy group, or arylaminocarbonyloxy group. Each of Rb60, Rb61 represents an alkyl group, aryl group, amino group, alkoxy group, or aryloxy group, and Rb60 and Rb61 may bind to each other to form a ring structure. Y6 represents an oxygen atom or sulfur atom.
In the above explanation of each group in the general formulae (B1) to (B13), the term xe2x80x9calkyl groupxe2x80x9d (including an alkyl group of a group having an alkyl group moiety, such as an alkylsulfonyl group) indicates a substituted or unsubstituted, linear, branched or cyclic alkyl having 1 to 30 carbon atoms, the term xe2x80x9caryl groupxe2x80x9d (including an aryl group of a group having an aryl group moiety, such as an arylsulfonyl group) indicates a substituted or unsubstituted, monocyclic or condensed-ring aromatic hydrocarbon ring such as a phenyl group and naphthyl group, and the term xe2x80x9cheterocyclic groupxe2x80x9d (including a heterocyclic group of a group having a heterocyclic group moiety, such as a heterocyclic amino group) indicates an aromatic or non-aromatic, monocyclic or condensed-ring, substituted or unsubstituted heterocyclic group containing at least one hetero atom.
Further, examples of the substituents herein are a halogen atom (fluorine atom, chlorine atom, bromine atom, or iodine atom), alkyl group (linear, branched or cyclic alkyl group, including bicycloalkyl group and active methine group), alkenyl group, alkynyl group, aryl group, heterocyclic group (regardless of position of substitution), acyl group, alkoxycarbonyl group, aryloxycarbonyl group, heterocyclicoxycarbonyl group, carbamoyl group, N-hydroxycarbamoyl group, N-acylcarbamoyl group, N-sulfonylcarbamoyl group, N-carbamoylcarbamoyl group, thiocarbamoyl group, N-sulfamoylcarbamoyl group, carbazoyl group, carboxy group or its salt, oxalyl group, oxamoyl group, cyano group, carbonimidoyl group, formyl group, hydroxy group, alkoxy group (including a group containing repeated ethyleneoxy group or propyleneoxy group units), aryloxy group, heterocyclicoxy group, acyloxy group, alkoxy- or aryloxy-carbonyloxy group, carbamoyloxy group, sulfonyloxy group, amino group, alkyl-, aryl- or heterocyclic-amino group, acylamino group, sulfonamido group, ureido group, thioureido group, N-hydroxyureido group, imido group, alkoxy- or aryloxy-carbonylamino group, sulfamoylamino group, semicarbazido group, thiosemicarbazido group, hydrazino group, ammonio group, oxamoylamino group, N-alkyl- or N-aryl-sulfonylureido group, N-acylureido group, N-acylsulfamoylamino group, hydroxyomino group, nitro group, heterocyclic group containing a quaternized nitrogen atom (such as pyridinio group, imidazolio group, quinolinio group, and isoquinolinio group), isocyano group, imino group, mercapto group, alkyl-, aryl- or heterocyclic-thio group, alkyl-, aryl- or heterocyclic-dithio group, alkyl- or aryl-sulfonyl group, alkyl- or aryl-sulfinyl group, sulfo group or a salt thereof, sulfamoyl group, N-acylsulfamoyl group, N-sulfonylsulfamoyl group or a salt thereof, phosphino group, phosphinyl group, phosphinyloxy group, phosphinylamino group, and silyl group. The term xe2x80x9cactive methine groupxe2x80x9d herein indicates a methine group substituted by two electron-withdrawing groups, and the term xe2x80x9celectron-withdrawing groupxe2x80x9d herein indicates an acyl group, alkoxycarbonyl group, aryloxycarbonyl group, carbamoyl group, alkylsulfonyl group, arylsulfonyl group, sulfamoyl group, trifluoromethyl group, cyano group, nitro group, and carbonimidoyl group. The two electron-withdrawing groups may bind to each other to form a ring structure. Further, the term xe2x80x9csaltxe2x80x9d indicates salt with a cation such as an alkaline metal, alkaline-earth metal or heavy metal, or with an organic cation such as an ammonium ion or phosphonium ion.
These substituents may be further substituted by the substituents.
In the general formulae (B1) to (B5), each of RN1, RN2, RN3, RN4, and RN5 is preferably a hydrogen atom or alkyl group. The alkyl group is preferably a linear, branched or cyclic, substituted or unsubstituted alkyl group preferably having 1 to 12 carbon atoms, more preferably a linear or branched, substituted or unsubstituted alkyl group having 1 to 6 carbon atoms. Examples of such an alkyl group are a methyl group, ethyl group, and benzyl group, etc.
In the general formula (B1), Rb1 is preferably an alkyl group or heterocyclic group. The alkyl group is a linear, branched or cyclic, substituted or unsubstituted alkyl group, preferably having 1 to 30 carbon atoms, more preferably having 1 to 18 carbon atoms. The heterocyclic group is 5- or 6-membered, monocyclic or condensed-ring, aromatic or non-aromatic heterocyclic group, which may have a substituent. The heterocyclic group is preferably an aromatic heterocyclic group, such as a pyridine ring group, pyrimidine ring group, triazine ring group, thiazole ring group, benzothiazole ring group, oxazole ring group, benzoxazole ring group, imidazole ring group, benzimidazole ring group, pyrazole ring group, indazole ring group, indole ring group, purine ring group, quinoline ring group, isoquinoline ring group, or quinazoline ring group. Especially preferable aromatic heterocyclic group is a triazine ring group or benzothiazole ring group. The alkyl group or heterocyclic group represented by Rb1 further having at least one or two xe2x80x94N(RN1)OH group as its substituent is also a preferable Example of the compound represented by the general formula (B1).
In the general formula (B2), Rb2 is preferably an alkyl group, aryl group, or heterocyclic group, more preferably an alkyl group or aryl group. A preferable range of the alkyl group is the same as that in the description of Rb1. The aryl group is preferably a phenyl group or naphthyl group, especially preferably a phenyl group. The aryl group may have a substituent. The group represented by Rb2 further having at least one or two xe2x80x94CON(RN2)OH group as its substituent is also a preferable Example of the compound represented by the general formula (B2).
In the general formula (B3), Rb3 is preferably an alkyl group or an aryl group, and their preferable ranges are the same as those described with respect to Rb1 and Rb2. RH3 is preferably a hydrogen atom, alkyl group, or hydroxy group, more preferably a hydrogen atom. The group represented by Rb3, further having at least one or two xe2x80x94N(RH3)CON(RN3)OH group as its substituent is also a preferable Example of the compound represented by the general formula (B3). Further, Rb3 and RN3 may bind to each other to form a ring structure (preferably a 5- or 6-membered saturated heterocycle). In the general formula (B4), Rb4 is preferably an alkyl group, and its preferable range is the same as that described with respect to Rb1. The group represented by Rb4, further having at least one or two xe2x80x94OCON(RN4)OH group as its substituent is also a preferable Example of the compound represented by the general formula (B4).
In the general formula (B5), Rb5 is preferably an alkyl group or aryl group, more preferably an aryl group, and their preferable ranges are the same as those described with respect to Rb1 and Rb2. Each of RH5 and Rxe2x80x2H5 are preferably a hydrogen atom or alkyl group, more preferably a hydrogen atom.
In the general formula (B6), Rb60 and Rb61 preferably bind to each other to form a ring structure. The ring structure formed by the above bonding is a 5- to 7-membered non-aromatic carbon ring or heterocycle, and may be a monocycle or condensed ring. Preferable specific examples of the ring structure are 2-cyclopentene-1-one ring, 2,5-dihydrofurane-2-one ring, 3-pyrroline-2-one ring, 4-pyrazoline-3-one ring, 2-cyclohexene-1-one ring, 5,6-dihydro-2H-pyran-2-one ring, 5,6-dihydro-2-pyridone ring, 1,2-dihydronaphthalene-2-one ring, coumarin ring (benzo-xcex1-pyran-2-one ring), 2-quinolone ring, 1,4-dihydronaphthalene-1-one ring, chromone ring (benzo-xcex3-pyran-4-one ring), 4-quinolone ring, indene-1-one ring, 3-pyrroline-2,4-dione ring, uracil ring, thiouracil ring, and dithiouracil ring, more preferably, 2-cyclopentene-1-one ring, 2,5-dihydrofuran-2-one ring, 3-pyrroline-2-one ring, 4-pyrazoline-3-one ring, 1,2-dihydronaphthalene-2-one ring, coumarin ring (benzo-xcex1-pyran-2-one ring), 2-quinolone ring, 1,4-dihydronaphthalene-1-one ring, chromone ring (benzo-xcex3-pyran-4-one ring), 4-quinolone ring, indene-1-one ring, and dithiouracil ring, and further preferably 2-cyclopentene-1-one ring, 2,5-dihydrofuran-2-one ring, 3-pyrroline-2-one ring, indene-1-one ring, and 4-pyrazoline-3-one ring.
When each of X6 and Xxe2x80x26 represents a cyclic amino group, the cyclic amino group is a non-aromatic nitrogen-containing heterocyclic group which binds to the carbon atom of the general formula (B6) via its nitrogen atom, such as a pyrrolidino group, piperidino group, piperazino group, morpholino group, 1,4-thiazine-4-yl group, 2,3,5,6-tetrahydro-1,4-thiazine-4-yl group, or indolyl group.
Preferable examples of X6 and Xxe2x80x26 are a hydroxy group, mercapto group, amino group (including alkylamino group, arylamino group, and cyclic amino group), acylamino group, sulfonamido group, acyloxy group, or acylthio group, more preferably a hydroxy group, mercapto group, amino group, alkylamino group, cyclic amino group, sulfonamido group, acylamino group, and acyloxy group, and especially preferably a hydroxy group, amino group, alkylamino group, and cyclic amino group. Further, at least one of X6 and Xxe2x80x26 is preferably a hydroxy group.
Y6 represents preferably an oxygen atom.
In the general formula (B7), each of R70 and Rb71 represents preferably a hydrogen atom, alkyl group or aryl group, more preferably an alkyl group. A preferable range of the alkyl group is the same as that described with respect to Rb1. Rb70 and Rb71 may bind to each other to form a ring structure (such as a pyrrolidine ring, piperidine ring, morpholino ring or thiomorpholino ring). Preferable examples of a substituent represented by Y7 are an alkyl group (its preferable range is the same as that described with respect to Rb1), alkoxy group, acylamino group, sulfonamide group, ureido group, acyl group, alkoxycarbonyl group, carbamoyl group, sulfamoyl group, chlorine atom, sulfo group or a salt thereof, carboxy group or a salt thereof. m7 represents preferably an integer of 0 to 2.
In the general formula (B8), m8 represents preferably an integer of 1 to 4, and plural Y8""s may be the same or different. When m8 is 1, Y8 is preferably an amino group (including alkylamino group, and arylamino group), sulfonamido group, or acylamino group. Also, when m8 is 2 or more, at least one of plural Y8""s is preferably an amino group (including alkylamino group, and arylamino group), sulfonamido group, or acylamino group, and each of the remaining Y8""s is preferably a sulfonamido group, acylamino group, ureido group, alkyl group, alkylthio group, acyl group, alkoxycarbonyl group, carbamoyl group, sulfo group or a salt thereof, carboxy group or a salt thereof or chlorine atom. If a oxe2x80x2-(or pxe2x80x2-)hydroxyphenylmethyl group serving as a substituent represented by Y8 is substituted at a ortho or para position of the hydroxy group in the general formula (B8), the general formula B8 represents a compound generally called bisphenols, which is also a preferable Example of a compound represented by the general formula (B8).
In the general formula (B9), the positions of substitution of the two hydroxy groups may be ortho positions (catechols), meta positions (resorcinols) or para positions (hydroquinones). m9 is preferably 1 to 2, and a plurality of Y9""s may be the same or different. Preferable examples of the substituent represented by Y9 are a chlorine atom, acylamino group, ureido group, sulfonamido group, alkyl group, alkylthio group, alkoxy group, acyl group, alkoxycarbonyl group, carbamoyl group, sulfo group or a salt thereof, carboxy group or a salt threreof, hydroxy group, alkylsulfonyl group, and arylsulfonyl group, etc. It is also a preferable Example that two adjacent Y9""s are bonded to each other to form a condensed benzene ring and consequently the general formula (B9) represents 1,4-naphthohydroquinones. When the general formula (B9) represents catechols, Y9 especially preferably represents a sulfo group or a salt thereof, or hydroxy group.
In the general formula (B10), when each of Rb100, Rb101 and Rb102 represents a substituent, preferable examples of the substituents are the same as the preferable examples of Y9. Among them, an alkyl group (in particular, methyl) is especially preferable. Preferable examples of a ring structure formed by Z10 are a chroman ring and 2,3-dihydrobenzofuran ring. The ring structure may have a substituent, and may form a spiro ring.
In the general formula (B11), preferable examples of Rb110, Rb111, Rb112 and Rb113 are an alkyl group, aryl group, and heterocyclic group, and their preferable ranges are the same as those described with respect to Rb1 and Rb2. Among them, an alkyl group is especially preferable, and two alkyl groups among Rb110 to Rb113 may be bonded to each other to form a ring structure. The ring structure is a 5- or 6-membered non-aromatic heterocycle, such as a pyrrolidine ring, piperidine ring, morpholino ring, thiomorpholino ring, or hexahydropyridazine ring, etc.
In the general formula (B12), Rb12 preferably represents an alkyl group, aryl group or heterocyclic group, and their preferable ranges are the same as those described with respect to Rb1 and Rb2. X12 preferably represents an alkyl group, aryl group (in particular, phenyl), heterocyclic group, alkoxy group, amino group (including alkylamino group, arylamino group, heterocyclic amino group and a cyclic amino group), or carbamoyl group, more preferably an alkyl group (especially preferably an alkyl group having 1 to 8 carbon atoms), aryl group (especially preferably phenyl), or amino group (including alkylamino group, arylamino group and cyclic amino group). Each of RH12 and Rxe2x80x2H12 preferably represents a hydrogen atom or alkyl group, more preferably a hydrogen atom.
In the general formula (B13), Rb13 preferably represents an alkyl group or aryl group, and their preferable ranges are the same as those described with respect to Rb1 and Rb2. Each of Rb130, Rb131, Rb132 and Rb133 preferably represents a hydrogen atom, alkyl group (especially preferably having 1 to 8 carbon atoms), or aryl group (especially preferably phenyl). RH13 preferably represents a hydrogen atom or acyl group, more preferably a hydrogen atom.
Among the compounds represented by the general formula (B1), the compounds of the general formula (B14) are preferred. 
wherein RN14 represents a hydrogen atom group or aryl group, and Z14 represents a nonmetallic atomic group capable of bonding with xe2x80x94Nxe2x95x90Cxe2x80x94 to thereby form a 5- to 7-membered heterocycle. As preferred heterocycles formed by Z14 and xe2x80x94Nxe2x95x90Cxe2x80x94, there can be mentioned the aromatic heterocycles mentioned with respect to the general formula (B1). The heterocycles are more preferably a pyrimidine ring group, triazine ring group, thiazole ring group, benzothiazole ring group, benzimidazole ring group, purine ring group, quinoline ring group and isoquinoline ring group. The heterocycles are further more preferably a pyrimidine ring group, triazine ring group, benzothiazole ring group, benzimidazole ring group and purine ring group, and most preferably a pyrimidine ring group, triazine ring group and benzothiazole ring group.
The heterocycles formed by Z14 and xe2x80x94Nxe2x95x90Cxe2x80x94 may each have a substituent which can be had by Rb1 in the general formula (B1), and the preferred range thereof is the same as that of Rb1 of the general formula (B1). Compounds having another xe2x80x94N(RN14)OH group, or two or more xe2x80x94N(RN14)OH groups as substituents are also included in the preferred examples of the compounds represented by the general formula (B14).
RN14 preferably represents a hydrogen atom or alkyl group. The preferred range of alkyl groups is the same as that of RN1 of the general formula (B1).
Among the compounds represented by the general formula (B2), the compounds of the general formula (B15) are preferred. 
wherein Rb15 represents a hydrogen atom, group, aryl group or heterocyclic group. The preferred range of alkyl groups, aryl groups or heterocyclic groups is the same as that of Rb2 of the general formula (B2).
Rb15 may have a substituent, and the preferred range thereof is the same as that of Rb2 of the general formula (B2). Compounds having another xe2x80x94N(CH3)OH group, or two or more xe2x80x94N(CH3)OH groups as substituents are also included in the preferred examples of the compounds represented by the general formula (B15).
In one aspect of the present invention, the silver halide photosensitive material of the present invention is characterized by containing at least one reducing compound having C/H of 3 or less and at least one reducing compound having a C/H value of more than 3. In another aspect of the present invention, the silver halide photosensitive material of the present invention is characterized by containing at least one reducing compound having a molecular weight of 300 or less, and at least one reducing compound having a molecular weight of more than 300. The reducing compound having a molecular weight of less than 300 used in the present invention preferably has a molecular weight of 30 or more, more preferably has a molecular weight of 60 to 300. On the other hand, the reducing compound having a molecular weight of more than 300 preferably has a molecular weight of 1,000 or less, more preferably has a molecular weight of 700 or less.
In the present invention, the C/H value is defined as a ratio of the number of Group IV elements/the sum of Group III, Group V, Group VI and Group VII elements, disregarding the elements of other groups (e.g., hydrogen) contained in the molecular structure. When a functional group capable of forming a salt (for example, a group capable of forming an onium salt by reaction with an acid, such as an amino group, or an anionic group such as a carboxyl group or sulfo group), is present in the molecule, the C/H value shall be calculated in free form (form wherein any salt is not formed).
The Group III, Group IV, Group V, Group VI and Group VII elements refer to the elements up to the fifth period of the IUPAC periodic table. That is, the Group IV elements refer to carbon (C), silicon (Si), germanium (Ge) and tin (Sn). The Group III elements refer to boron (B), aluminum (Al), gallium (Ga) and indium (In). The Group V elements refer to nitrogen (N), phosphorus (P), arsenic (As) and antimony (Sb). The Group VI elements refer to oxygen (O), sulfur (S), selenium (Se) and tellurium (Te). The Group VII elements refer fluorine (F), chlorine (Cl), bromine (Br) and iodine (I).
In the present invention, the molecular weight generally refers to that calculated from the structural formula and composition formula of compound and the mass numbers of individual elements. When a particular compound in its molecule has a functional group capable of forming a salt (for example, a group capable of forming an onium salt by reaction with an acid, such as an amino group, or an anionic group such as a carboxyl group or sulfo group, is present in the molecule, the molecular weight of the compound refers to that calculated in free form (form wherein any salt is not formed).
In the present invention, the reducing compound may also be one having, incorporated in its molecule, a ballasting group or polymer chain customarily employed in immobilized photographic additives such as couplers. Herein, the ballasting group refers to a group having a linear, branched or cyclic alkyl group (or alkylene group) having 6 or more carbon atoms as a partial structure, which may be unsubstituted or substituted. This alkyl group (or alkylene group) can be bonded to any arbitrary position of the reducing compound of the present invention by means of an arbitrary linking group.
Herein, the linking group refers to one which consists of any one of groups such as an alkylene group, arylene group, heterocyclic group, a single bond, xe2x80x94Oxe2x80x94, xe2x80x94NRNxe2x80x94, xe2x80x94Sxe2x80x94, xe2x80x94Cxe2x95x90Oxe2x80x94, xe2x80x94SO2xe2x80x94, xe2x80x94Cxe2x95x90Sxe2x80x94, xe2x80x94SOxe2x80x94 and xe2x80x94Pxe2x95x90Oxe2x80x94, or a polyvalent group consisting of combination of two or more these groups.
The above RN represents a hydrogen atom, alkyl group, aryl group or heterocyclic group. The linking group may further have any arbitrary substituent.
The ballasting group is preferably a group having a linear or branched alkyl group (or alkylene group) having 8 to 24 carbon atoms as a partial structure.
As the polymer, there can be mentioned, for example, those described in JP-A-1-100530, the entire contents of which are incorporated herein by reference.
Still further, the reducing compound of the present invention may be one having a group adsorptive to silver halide incorporated in its molecule.
In the present invention, the reducing compound having at least one group adsorptive to silver halide refers to a compound whose structure agrees with that of any of the general formulae (B1) to (B13), which compound has in its molecule a group adsorptive to silver halide which may be possessed by the compounds of types 1 to 5 described above.
The reducing compound of the present invention is preferably one selected from hydroxylamines represented by the general formula (B1), hydroxamic acids represented by the general formula (B2), hydroxylureas represented by the general formula (B3), hydroxylurethanes represented by the general formula (B4), hydroxysemicarbazides represented by the general formula (B5), phenols represented by the general formulae (B8), (B9) and (B10) (including chroman-6-ols, hydroquinones, catechols, resorcinols, bisphenols and the like), hydrazines represented by the general formula (B11), Phenidones represented by the general formula (B13) and reductones represented by the general formula (B6) (including reductone derivatives). The reducing compound of the present invention is more preferably one selected from among hydroxylamines, hydroxamic acids, hydroxyureas, hydroxysemicarbazides, phenols, hydrazines and reductones.
Among the compounds represented by the general formula (B1), hydroxylamines represented by the general formula (B14) are especially preferred. Among the compounds represented by the general formula (B2), hydroxamic acids represented by the general formula (B15) are especially preferred.
As the reducing compound having a C/H value of 3 or less according to the present invention, there can preferably be employed hydroxylamines, hydroxamic acids, hydroxyureas, phenols, reductones and hydrazines.
Also, as the reducing compound having a C/H value of more than 3 according to the present invention, there can preferably be employed hydroxylamines, hydroxamic acids, hydroxyureas, hydroxyurethanes, phenols and reductones.
As the reducing compound having a molecular weight of 300 or less according to the present invention, there can preferably be employed hydroxylamines, hydroxamic acids, hydroxyureas, phenols, reductones and hydrazines.
Also, as the reducing compound having a molecular weight of more than 300 according to the present invention, there can preferably be employed hydroxylamines, hydroxamic acids, hydroxyureas, hydroxyurethanes, phenols and reductones.
An oxidation potential of each of the reducing compounds according to the present invention can be measured by using measuring methods described in xe2x80x9cDENKIKAGAKU SOKUTEIHOU (Electrochemical Measuring method)xe2x80x9d (pp. 150-208, GIHODO SHUPPAN Co. Ltd.) and xe2x80x9cJIKKEN KAGAKU KOUZA (Experimental chemical Course)xe2x80x9d the 4th Edition, edited and written by Chemical Society of Japan (Vol. 9, pages 282 to 344, published by Maruzen Co., Ltd.). For example, there is a method of rotary disc voltammetry. Specifically, a sample is dissolved in a solution of xe2x80x9cmethanol:Britton-Robinson buffer (pH 6.5)=10%:90% (volume %)xe2x80x9d, a nitrogen gas is passed therethrough for 10 minutes, and thereafter the oxidation potential can be measured at 25xc2x0 C., 1000 rotation per minute, and a sweep speed of 20 mV/s, by using a rotary disc electrode (RDE) made of glassy carbon as a working electrode, a platinum wire as a counter electrode, and a saturated calomel electrode as a reference electrode. A half-wave potential (E1/2) can be determined based on the obtained voltammogram.
The oxidation potential of the reducing compounds according to the present invention preferably falls within, if measured by the above method, the range of about xe2x88x920.3 V to 1.0 V, more preferably about xe2x88x920.1 V to 0.8 V, especially preferably about 0 to 0.7 V.
The following are examples of the reducing compounds according to the present invention, however, the present invention is not limited to them.
The numbers in parentheses set forth under each reducing compound are [molecular weight/C/H value]. 
As other examples of the reducing compounds of the present invention, there can be mentioned compounds represented by the general formulae (II) to (VI), together with examples thereof, described in JP-A-2001-42466, the entire contents of which are incorporated herein by reference. Further, there can be mentioned compound examples described in the literature and patents cited therein.
In the present invention, although use is made of a compound selected from among reducing compounds having a C/H value of 3 or less and a compound selected from among reducing compounds having a C/H value of more than 3, it is also preferred to simultaneously use two or more compounds selected from among each of the reducing compound groups.
When two or more types selected from among the reducing compounds having a C/H value of 3 or less and/or the reducing compounds having a C/H value of more than 3 are employed, they may be added to the same layer or different layers. Also, different addition methods may be adopted.
Further, in the present invention, although use is made of a compound selected from reducing compounds having a molecular weight of 300 or less and a compound selected from reducing compounds having a molecular weight of more than 300, it is also preferred to simultaneously use two or more compounds selected from among each of the reducing compound groups.
When two or more types selected from the reducing compounds having a molecular weight of 300 or less and/or the reducing compounds having a molecular weight of more than 300 are employed, they may be added to the same layer, or different layers. Also, different addition methods may be adopted.
The reducing compound having a C/H value of 3 or less, that having a C/H value of more than 3, that having a molecular weight of 300 or less, and that having a molecular weight of more than 300, may be added to an emulsion or a silver halide photosensitive material by various methods in accordance with the property of respective compounds.
For example, the reducing compounds may be dissolved in water or a water soluble solvent, such as methanol or ethanol, or a mixed solvent therefrom before the addition. The pH value of the solution may be appropriately regulated with the use of an acid or a base, and further a surfactant may be incorporated therein.
Also, the reducing compounds may be dissolved in a soluble organic solvent, or dissolved in a high-boiling organic solvent into an emulsified dispersion, before the addition. Further, these reducing compounds may be added in the form of solid dispersion (microcrystal dispersion) formed by the use of known dispersing methods.
Those having an adsorptive group among the reducing compounds of the present invention are preferably added to silver halide emulsion layers. More preferably, the addition is performed at the time of emulsion preparation. When the addition is performed at the time of emulsion preparation, the addition may be carried out at any stage during the process. For example, the stage at which the addition is effected can be during the formation of silver halide grains, before the initiation of desalting, during desalting, before the initiation of chemical ripening, during chemical ripening, before the preparation of final emulsion, etc. Further, divided additions can be effected at each of these stages. Although the addition is preferably effected to emulsion layers, it is also practicable to effect the addition to not only an emulsion layer but also adjacent protective layer or interlayer so as to realize diffusion at the coating time.
The preferred addition amount thereof, although largely depending on the above addition method or added compound species, is generally in the range of 1xc3x9710xe2x88x928 to 5xc3x9710xe2x88x922 mol, preferably 1xc3x9710xe2x88x927 to 1xc3x9710xe2x88x923 mol per mol of lightsensitive silver halides.
Those not having any adsorptive group or ballasting group among the reducing compounds of the present invention can be added to not only silver halide emulsion layers but also other non-lightsensitive layers. Although the addition is preferably effected to emulsion layers, it is also practicable to effect the addition to not only an emulsion layer but also adjacent protective layer or interlayer so as to realize diffusion at the coating time. Although the addition can be effected at the time of emulsion preparation before chemical sensitization, during chemical sensitization or after the completion of chemical sensitization, it is preferred to effect the addition before the application of coating liquid or at the coating time.
The preferred addition amount thereof, although largely depending on the above addition method or added compound species, is generally in the range of 5xc3x9710xe2x88x926 to 5xc3x9710xe2x88x922 mol, preferably 1xc3x9710xe2x88x925 to 1xc3x9710xe2x88x923 mol per mol of lightsensitive silver halides.
Those having a ballasting group among the reducing compounds of the present invention can be added to not only silver halide emulsion layers but also other non-lightsensitive layers. Although the addition is preferably effected to emulsion layers, it is also practicable to effect the addition to not only an emulsion layer but also adjacent protective layer or interlayer so as to realize diffusion at the coating time. Although the addition may be effected at the time of emulsion preparation, it is preferred to effect the addition through emulsification dispersion.
The preferred addition amount thereof, although largely depending on the above addition method or added compound species, is generally in the range of 5xc3x9710xe2x88x925 to 5xc3x9710xe2x88x921 mol, preferably 1xc3x9710xe2x88x924 to 1xc3x9710xe2x88x921 mol per mol of lightsensitive silver halides.
Next, silver halide emulsions that may be used in the present invention will be described.
The silver halide grains for a photographic emulsion may have a regular crystal shape such as cube, octahedron, tetradecahedron, rhombododecahedron, or irregular crystal shape such as sphere or plate. In addition, the silver halide grains may have a face of a high order ((hkl) face), or may be a mixture of grains having these crystal shapes. Preferably the silver halide grains are tabular grains, which will be detailed below. With regard to the grains having a face of a high order reference can be made to Journal of Imaging Science, vol. 30 (1986), pp. 247-254.
The photosensitive material of the present invention preferably contains a lightsensitive silver halide emulsion containing tabular grains (silver halide grains each having two parallel main planes, hereinafter referred to as xe2x80x9ctabular grainsxe2x80x9d). The silver halide grains will be described in detail below.
The aspect ratio of each silver halide grain of the present invention is defined as a value obtained by dividing an equivalent circle diameter of the two facing parallel main planes (a diameter of a circle having the same projected area as that of the main plane) of each grain by a distance between the main planes (that is, the thickness of the grain).
The aspect ratio of tabular grains is preferably 5 to 100. In order to attain the advantages of the present invention, the aspect ratio of the tabular grains is preferably 8 to 60, more preferably 10 to 30. When the average aspect ratios less than 2 or those greater than 100 are undesirable because if the average aspect ratio is less than 2, the merit of the tabular grains cannot be fully used and because if the average aspect ratio exceeds 100, the pressure resistance deteriorates. Further, as for the emulsion used in the present invention, the ratio occupied by the tabular grains is preferably 60% or more, more preferably 80% or more, and particularly preferably 90% or more of the total projected area of the emulsion. When the ratio occupied by tabular grains is less than 50%, the merits of tabular grains cannot be fully used, which is not preferable.
The average grain thickness in the present invention is an arithmetical average of the thickness of all the tabular grains. The average grain thickness of the tabular grains of the present invention is preferably 0.01 to 0.3 xcexcm, more preferably 0.01 to 0.12 xcexcm, and particularly preferably 0.01 to 0.07 xcexcm. When the average grain thickness is less than 0.01 xcexcm pressure resistance deteriorates, while when it exceeds 0.3 xcexcm the advantages of the present invention is difficult to attain, which are not preferable.
In the present invention, the grain thickness and aspect ratio within the above mentioned ranges may be selected depending on purposes, but tabular grains having thin thickness and high aspect ratio are preferably used.
In the present invention, the diameter (equivalent circle diameter) of the tabular grains may be selected arbitrary, but is preferably 0.3 to 20 xcexcm, and more preferably 0.5 to 10 xcexcm. When the average equivalent circle diameter, which is an arithmetical average of the equivalent circle diameter of all the tabular grains, is less than 0.3 xcexcm the advantages of the present invention is difficult to attain, while when it is more than 20 xcexcm pressure resistance deteriorates, which are not preferable.
The grain diameter and the grain thickness can be obtained from an electron micrograph according to the method disclosed in U.S. Pat. No. 4,434,226. One Example of an aspect ratio measurement method comprises taking a transmission electron micrograph by a replica method and obtaining the diameter of a circle whose area is the same as the projected area of each grain (the equivalent circle diameter) and the thickness of each grain. In this method, the thickness can be calculated from the length of a shadow of replica.
It is preferable that the tabular grains used in the present invention be monodisperse. The variation coefficient of the grain diameter distribution of all the silver halide grains is preferably 35% or less, more preferably 25% or less, and particularly preferably 20% or less. When the variation coefficient exceeds 35%, it is not undesirable from the viewpoint of uniformity among grains. The variation coefficient of grain diameter distribution is a value obtained in such a manner that a distribution (standard deviation) of the equivalent sphere diameters of the silver halide grains is divided by the average equivalent sphere diameter and the resulting value is multiplied by 100. The grain size distribution of silver halide emulsion composed of silver halide grains of matched grain shape and of small grain size variation, show substantially normal distribution, thus the standard deviation can be easily obtained.
Preparation method of monodisperse tabular grains is described in the specification of JP-A-63-11928. That of monodisperse hexagonal tabular grains is described in the specification of JP-A-63-151618. That of circular monodisperse tabular grain emulsion is described in the specification of JP-A-1-131541. Further, an emulsion occupied by tabular grains having two twin planes that are parallel to a main plane in an amount of 95% or more and the size distribution of the tabular grains is monodisperse, is described in the specification of JP-A-2-838. A tabular grain emulsion prepared by using polyalkylene oxide block copolymer and having a variation coefficient of grain size of 10% or less, is described in the specification of EP 514742A1.
There are known the tabular grains whose main planes are (100) planes and the tabular grains whose main planes are (111) planes, to both of which the technique of the present invention can be applied. The tabular grains of the former type made of silver bromide are disclosed in the specification of U.S. Pat. No. 4,063,951 and JP-A-5-281640, while the tabular grains of the former type made of silver chloride are disclosed in the specifications of EP 5343955 A1 and U.S. Pat. No. 5,264,337. The tabular grains of the latter type can have various shapes wherein at least one above mentioned twin plane is present, and those of silver chloride are described in the specifications of U.S. Pat. Nos. 4,399,215, 4,983,508 and 5,183,732, and JP-A""s-3-137632 and 3-116113.
As a method for forming the tabular grains, various methods can be used and, for example, the grain forming method disclosed in the specification of U.S. Pat. No. 5,494,789 can be used. In order to form tabular grains having a high aspect ratio, it is important to grow twin nuclei of small sizes. For this purpose, it is preferable to grow the nuclei at low temperature, high pBr and low pH, using a small amount of gelatin in a short time. As the kind of gelatin, gelatin with a low molecular weight, gelatin with a low methionine content, gelatin that has been phthalated, and the like are preferred.
After the formation of the nuclei, physical ripening is carried out to grow only tabular grain nuclei (parallel, multiple-layered twin nuclei) by eliminating other nuclei, i.e., nuclei of normal crystal habit, single-layered twin nuclei and non-parallel, multiple-layered twin nuclei, thereby causing the parallel, multiple-layered twin nuclei to remain selectively. Then, a soluble silver salt and a soluble halogen salt are added to the obtained nuclei to promote grain growth, and an emulsion comprising tabular grains is prepared.
It is also preferable to grow grains by supplying silver and halide through the addition of silver halide fine grains that have been prepared separately in advance or that are simultaneously prepared in another reaction vessel.
The tabular grains in the present invention may have a dislocation line. When tabular grains in the present invention have dislocation lines, the dislocation lines may be formed, for example, on the apex portion or fringe portion of grains or on the main plane of gains. As used herein, the fringe portion is the periphery of a tabular grain. More specifically, in the distribution of silver iodide from the edge to the center of a tabular grain, the fringe portion is a region outside a certain point at which the silver iodide content exceeds or becomes lower than the average silver iodide content of the whole grain for the first time when viewed from the edge.
When tabular grains have dislocation lines, the density of the dislocation lines is optional and any density may be selected, for example, 10 lines or more, 30 lines or more, 50 lines or more, per grain. The tabular grains used in the present invention may have a dislocation line inside the grain.
A technique of introducing, with control, dislocation in silver halide grains is described in JP-A-63-220238. It is demonstrated that tabular grain to which a dislocation line is introduced, compared with tabular grain having no dislocation line, can attain advantages such as improved photographic properties such as speed, reciprocity law, etc, an improvement in storability, an enhancement of latent image stability, a reduction of pressure mark, etc. According to the invention described in the publication, dislocation is introduced in the edge portion of tabular grain. Further, tabular grain to the central portion of which dislocation is introduced, is described in the specification of U.S. Pat. No. 5,238,796.
Dislocation lines in tabular grains can be observed by, for example, a direct method using a transmission electron microscope at low temperature described, for example, in J. F. Hamilton, Photo. Sci. Eng., 11, 57(1967) and T. Shiozawa, J. Soc. Photo. Sci. Japan, 35, 213 (1972). That is, silver halide grains, extracted carefully from an emulsion so as not to apply a pressure at which dislocations are produced in the grains, are placed on a mesh for electron microscopic observation. Observation is performed by a transmission method while the sample is cooled to prevent damage (e.g., print out) due to electron rays. In this case, the greater the thickness of a grain, the more difficult it becomes to transmit electron rays through it. Therefore, grains can be observed more clearly by using an electron microscope of high voltage type (200 kV or more for a grain having a thickness of 0.25 xcexcm). From photographs of grains obtained by the above method, it is possible to obtain the positions and the number of dislocation lines in each grain viewed in a direction perpendicular to the main planes of the grain.
As the silver halide grains used in the present invention, silver bromide, silver chlorobromide, silver iodobromide, silver iodochloride, silver chloride, silver chloroiodobromide and the like can be used. It is preferable to use silver bromide, silver iodobromide, and silver chloroiodobromide.
It is also preferable, in respect of rapid processing property, to use silver chlorobromide, silver chloroiodide, silver chloroiodobromide, containing 50 mol % or more of silver chloride, or silver chloride, and having an aspect ratio of 2 or more. Although the upper limit of the silver chloride content is not specifically set, the silver chloride content is preferably 99.6% or less.
When the silver halide grains have a phase containing iodide or chloride, the phase may be uniformly distributed within the grain or they may be localized. Other silver salts, such as silver rhodanide, silver sulfide, silver selenide, silver carbonate, silver phosphate and silver salts of organic acids, may be contained as separate grains or as part of the silver halide grains.
The preferable range of silver iodide content in the tabular grains of the present invention is preferably 0.1 to 20 mol %, more preferably 0.1 to 15 mol %, and particularly preferably 0.2 to 10 mol %. A silver iodide content less than 0.1 mol % is undesirable because it is difficult to obtain the advantages of enhancing dye adsorption and increasing the intrinsic sensitivity. A silver iodide content exceeding 20 mol % is also undesirable because the developing speed generally lowers.
Although tabular grains containing 50 mol % or more of silver chloride and having an aspect ratio of 2 or more may contain silver iodide, its silver iodide content is preferably 6 mol % or less, more preferably 2 mol % or less.
The variation coefficient of distribution of silver iodide contents among grains of the tabular grains used in the present invention is preferably 30% or less, more preferably 25% or less, and particularly preferably 20% or less. If it exceeds 30%, it is not preferable from the viewpoint of uniformity among grains. The silver iodide content of individual tabular grain can be measured by analyzing the composition of the grain one by one with an X-ray microanalyzer. The coefficient of variation of distribution of silver iodide content used herein is a value obtained by dividing the standard deviation of the silver iodide content of individual grain by the average silver iodide content.
The tabular grains in the present invention may be epitaxial silver halide grains comprising host tabular grains having, on surfaces thereof, at least one kind of silver salt epitaxy.
In the present invention, a silver salt epitaxy may be formed in selected portions in the surface of a host tabular grain, and alternatively, may be formed restrictedly in corners and edges of the host tabular grain (that is, grain side faces and on the edge of each edge, respectively, when the grain is viewed from above).
In the case of forming a silver salt epitaxy, it is preferable to form the silver salt epitaxy in selected sites in the surfaces of host tabular grains uniformly in individual grain and between the grains. As a concrete site-direct method of a silver salt epitaxy, there are known a method, which is disclosed in U.S. Pat. No. 4,435,501, of causing host grains to adsorb a spectral sensitizing dye (for example, a cyanine dye) or an aminoazaindene (for example, adenine) before the formation of the silver salt epitaxy, a method of causing host grains to contain silver iodide, and the like. These methods may be employed. Further, it is also possible to add iodide ions before the formation of the silver salt epitaxy, thereby precipitating them on host grains. These site-directing methods may be chosen case by case and may be employed in combination of them.
In the case of forming a silver salt epitaxy, the ratio of the area occupied by the silver salt epitaxy with respect to the surface area of the host tabular grain on which the silver salt epitaxy is formed is preferably 1 to 50%, more preferably 2 to 40%, and particularly preferably 3 to 30%.
In the case of forming a silver salt epitaxy, the amount of silver in the silver salt epitaxy relative to the total amount of silver in the silver halide tabular grains is preferably 0.3 to 50 mol %, more preferably 0.3 to 25 mol %, and particularly preferably 0.5 to 15 mol %.
The composition of the silver salt epitaxy can be selected depending on a situation, and it may be silver halide containing any of a chloride ion, a bromide ion and an iodide ion. However, it is preferably a silver halide containing at least a chloride ion. Silver chloride easily forms an epitaxy because it forms a face-centered cubic lattice structure that is the same as silver bromide and silver iodobromide, which form host tabular grains. However, there is a difference between the lattice spaces formed of two kinds of silver halides, and therefore, this will cause the formation of an epitaxy junction which contributes the increase in photographic sensitivity.
The content of the silver chloride contained in a silver halide epitaxy is preferably greater than the content of the silver chloride contained in host tabular grains by at least 10 mol %, more preferably by at least 15 mol %, and particularly preferably by at least 20 mol %. A difference between the silver chloride contents of the epitaxy and the host of less than 10 mol % is undesirable because it makes the effect difficult to be obtained.
In the introduction of a halide ion to a silver halide epitaxy, it is preferable, for the purpose of increasing its introduction amount, to introduce a halide ion in the order depending on the composition of the epitaxy. For example, when forming an epitaxy in which a greater amount of silver chloride is contained in the inside portion, a greater amount of silver bromide is contained in the intermediate portion and a greater amount of silver iodide is contained in the outside portion, the addition of these halide ions is conducted in the order, a chloride ion, a bromide ion and then an iodide ion, thereby making the solubility of a silver halide containing the halide ion added smaller than the solubilities of the other silver halides to precipitate the silver halide, thereby forming a layer rich in the silver halide. Silver salts other than silver halides, such as silver rhodanide, silver sulfide, silver selenide, silver carbonate, silver phosphate and silver salts of organic acids, may be contained in a silver salt epitaxy.
Examples of a method for forming a silver salt epitaxy include a method of adding a halide ion, a method of adding an aqueous silver nitride solution and an aqueous halide solution by the double jet method, and a method of adding silver halide fine grains. These methods may be selected case by case and also may be used in combination. In the formation of a silver salt epitaxy, the temperature, pH and pAg of the system, the kind and concentration of a protective colloid such as gelatin, the presence, kind and concentration of a silver halide solvent, and the like may be selected widely.
In the case of an epitaxial silver halide grain, for maintaining the form of a host tabular grain or site-directing of a silver salt epitaxy to the edge/corner sites of the grain, it is preferable that the silver iodide content in the outside region, this being the portion that precipitates lastly and forming the edge/corner sites of the grain, of the host tabular grain is at least 1 mol % higher than the silver iodide content in the center region. At this time, the silver iodide content in the outside region is preferably 1 to 20 mol %, and more preferably 5 to 15 mol %. A content of less than 1 mol % is undesirable because the above-described effect cannot be obtained. A content exceeding 20 mol % is also undesirable because the development speed lowers. In this case, the ratio of the total silver amount in the outside region containing silver iodide relative to the total silver amount of the host tabular grains is preferably 10 to 30% and more preferably 10 to 25%. An mount less than 10% and an amount exceeding 30% are undesirable because the above-described effect cannot be obtained. At this time, the silver iodide content in the center region is preferably 0 to 10 mol %, more preferably 1 to 8 mol %, and particularly preferably 1 to 6 mol %. A content exceeding 10 mol % is undesirable because the development speed lowers.
An oxidizer capable of oxidizing silver is preferably used during the process of producing the emulsion for use in the present invention. The silver oxidizer is a compound having an effect of acting on metallic silver to thereby convert the same to silver ion. A particularly effective compound is one that converts very fine silver grains, formed as a by-product in the step of forming silver halide grains and the step of chemical sensitization, into silver ions. Each silver ion produced may form a silver salt sparingly soluble in water, such as a silver halide, silver sulfide or silver selenide, or may form a silver salt easily soluble in water, such as silver nitrate.
The silver oxidizer may be either an inorganic or an organic substance. Examples of suitable inorganic oxidizers include ozone, hydrogen peroxide and its adducts (e.g., NaBO2.H2O2.3H2O, 2NaCO3.3H2O2, Na4P2O7.2H2O2 and 2Na2SO4.H2O2.2H2O), peroxy acid salts (e.g., K2S2O8, K2C2O6 and K2P2O8), peroxy complex compounds (e.g., K2[Ti(O2)C2O4].3H2O, 4K2SO4.Ti(O2)OH.SO4.2H2O and Na3[VO(O2)(C2H4)2].6H2O), permanganates (e.g., KMnO4), chromates (e.g., K2Cr2O7) and other oxyacid salts, halogen elements such as iodine and bromine, perhalogenates (e.g., potassium periodate), salts of high-valence metals (e.g., potassium hexacyanoferrate(II)) and thiosulfonates.
Examples of suitable organic oxidizers include quinones such as p-quinone, organic peroxides such as peracetic acid and perbenzoic acid and active halogen-releasing compounds (e.g., N-bromosuccinimide, chloramine T and chloramine B).
Oxidizers preferred in the present invention are inorganic oxidizers selected from among ozone, hydrogen peroxide and its adducts, halogen elements and thiosulfonates and organic oxidizers selected from quinones. A combined use of the reducing sensitizer with the oxidizer to silver is a preferable embodiment. A method of performing reduction sensitization after the oxidizer is used or a method of vice versa, or a method of making both compounds coexist simultaneously, may be selected and used. These methods may be selected and used in the grain formation step or chemical sensitization step.
It is advantageous to use gelatin as a protective colloid for use in preparation of emulsions of the invention or as a binder for other hydrophilic colloid layers. However, another hydrophilic colloid can also be used in place of gelatin.
Examples of the hydrophilic colloid are protein, such as a gelatin derivative, a graft polymer of gelatin and another high polymer, albumin, and casein; sugar derivatives, such as cellulose derivatives, e.g., cellulose sulfates, hydroxyethylcellulose, and carboxymethylcellulose, soda alginate, and starch derivatives; and a variety of synthetic hydrophilic high polymers, such as homopolymers or copolymers, e.g., polyvinyl alcohol, polyvinyl alcohol with partial acetal, poly-N-vinylpyrrolidone, polyacrylic acid, polymethacrylic acid, polyacrylamide, polyvinylimidazole, and polyvinylpyrazole.
Examples of gelatin are lime-processed gelatin, acid-processed gelatin, and enzyme-processed gelatin described in Bull. Soc. Sci. Photo. Japan, 16, page 30 (1966). In addition, a hydrolyzed product or an enzyme-decomposed product of gelatin can also be used.
It is preferable to wash with water an emulsion of the present invention to desalt, and disperse into a newly prepared protective colloid. Although the temperature of washing can be selected in accordance with the intended use, it is preferably 5xc2x0 C. to 50xc2x0 C. Although the pH of washing can also be selected in accordance with the intended use, it is preferably 2 to 10, and more preferably, 3 to 8. The pAg of washing is preferably 5 to 10, though it can also be selected in accordance with the intended use. The washing method can be selected from noodle washing, dialysis using a semipermeable membrane, centrifugal separation, coagulation precipitation, and ion exchange. The coagulation precipitation can be selected from a method using sulfate, a method using an organic solvent, a method using a water-soluble polymer, and a method using a gelatin derivative.
In the preparation of the emulsion of the invention, it is preferable to make salt of metal ion exist, for example, during grain formation, desalting, or chemical sensitization, or before coating in accordance with the intended use. The metal ion salt is preferably added during grain formation when doped into grains, and after grain formation and before completion of chemical sensitization when used to modify the grain surface or used as a chemical sensitizer. The salt can be doped in any of an overall grain, only the core portion or the shell portion of a grain. Examples of the dopant are Mg, Ca, Sr, Ba, Al, Sc, Y, La, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ru, Rh, Pd, Re, Os, Ir, Pt, Au, Cd, Hg, Tl, In, Sn, Pb, and Bi.
These metals can be added as long as they are in the form of salt that can be dissolved during grain formation, such as ammonium salt, acetate, nitrate, sulfate, phosphate, hydroxide, hexa-coordinated complex salt, or ttetra-coordinated complex salt. Examples are CdBr2, CdCl2, Cd(NO3)2, Pb(NO3)2, Pb(CH3COO)2, K3[Fe(CN)6], (NH4)4[Fe(CN)6], K4[Fe(CN)6], K2IrCl6, K3IrCl6, (NH4)3RhCl6, and K4Ru(CN)6. The ligand of a coordination compound can be selected from halo, aquo, cyano, cyanate, thiocyanate, nitrosyl, thionitrosyl, oxo, and carbonyl. These metal compounds can be used either singly or in the form of a combination of two or more types of them.
The metal compounds are preferably dissolved in an appropriate solvent, such as methanol or acetone, and added in the form of a solution. To stabilize the solution, an aqueous hydrogen halogenide solution (e.g., HCl or HBr) or an alkali halide (e.g., KCl, NaCl, KBr, or NaBr) can be added. It is also possible to add acid or alkali if necessary. The metal compounds can be added to a reactor vessel either before or during grain formation. Alternatively, the metal compounds can be added to a water-soluble silver salt (e.g., AgNO3) or an aqueous alkali halide solution (e.g., NaCl, KBr, or KI) and added in the form of a solution continuously during formation of silver halide grains. Furthermore, a solution of the metal compounds can be prepared independently of a water-soluble salt or an alkali halide and added continuously at a proper timing during grain formation. It is also possible to combine several different addition methods.
It is sometimes useful to perform a method of adding a chalcogen compound during preparation of an emulsion, such as described in U.S. Pat. No. 3,772,031. In addition to S, Se, and Te, cyanate, thiocyanate, selenocyanic acid, carbonate, phosphate, and acetate can be present.
In the silver halide grains used in the invention, at least one of chalcogen sensitization including sulfur sensitization and selenium sensitization, and noble metal sensitization including gold sensitization and palladium sensitization, and reduction sensitization can be performed at any point during the process of preparing a silver halide emulsion. The use of two or more different sensitizing methods is preferable.
Several different types of emulsions can be prepared by changing the timing at which the chemical sensitization is performed. The emulsion types are classified into: a type in which a chemical sensitization nucleus is embedded inside a grain, a type in which it is embedded in a shallow position from the surface of a grain, and a type in which it is formed on the surface of a grain. In emulsions of the present invention, the position of a chemical sensitization nucleus can be selected in accordance with the intended use. However, it is generally preferable to form at least one type of a chemical sensitization nucleus in the vicinity of the surface.
One chemical sensitization which can be preferably performed in the present invention is chalcogen sensitization, noble metal sensitization, or a combination of these. The sensitization can be performed by using active gelatin as described in T. H. James, The Theory of the Photographic Process, 4th ed., Macmillan, 1977, pages 67 to 76. The sensitization can also be performed by using any of sulfur, selenium, tellurium, gold, platinum, palladium, and iridium, or by using a combination of a plurality of these sensitizers at pAg 5 to 10, pH 5 to 8, and a temperature of 30xc2x0 C. to 80xc2x0 C., as described in Research Disclosure, Vol. 120, April, 1974, 12008, Research Disclosure, Vol. 34, June, 1975, 13452, the specifications of U.S. Pat. Nos. 2,642,361, 3,297,446, 3,772,031, 3,857,711, 3,901,714, 4,266,018, and 3,904,415, and British Patent 1,315,755. In the noble metal sensitization, salts of noble metals, such as gold, platinum, palladium, and iridium, can be used. In particular, gold sensitization, palladium sensitization, or a combination of the both is preferred.
In the gold sensitization, it is possible to use known compounds, such as chloroauric acid, potassium chloroaurate, potassium aurithiocyanate, gold sulfide, and gold selenide. A palladium compound means a divalent or tetravalent salt of palladium. A preferable palladium compound is represented by R2PdX6 or R2PdX4 wherein R represents a hydrogen atom, an alkali metal atom, or an ammonium group and X represents a halogen atom, e.g., a chlorine, bromine, or iodine atom.
More specifically, the palladium compound is preferably K2PdCl4, (NH4)2PdCl6, Na2PdCl4, (NH4)2PdCl4, Li2PdCl4, Na2PdCl6, or K2PdBr4. It is preferable that the gold compound and the palladium compound be used in combination with thiocyanate or selenocyanate.
Examples of a sulfur sensitizer are hypo, a thiourea-based compound, a rhodanine-based compound, and sulfur-containing compounds described in U.S. Pat. Nos. 3,857,711, 4,266,018, and 4,054,457. The chemical sensitization can also be performed in the presence of a so-called chemical sensitization aid. Examples of a useful chemical sensitization aid are compounds, such as azaindene, azapyridazine, and azapyrimidine, which are known as compounds capable of suppressing fog and increasing sensitivity in the process of chemical sensitization. Examples of the chemical sensitization aid and the modifier are described in U.S. Pat. Nos. 2,131,038, 3,411,914, and 3,554,757, JP-A-58-126526, and the above mentioned G. F. Duffin, Photographic Emulsion Chemistry, pages 138 to 143.
A preferable amount of a sulfur sensitizer used in the invention is 1xc3x9710xe2x88x924 to 1xc3x9710xe2x88x927 mol, and more preferably, 1xc3x9710xe2x88x925 to 5xc3x9710xe2x88x927 mol per mol of a silver halide. A preferable range of the palladium compound is 1xc3x9710xe2x88x923 to 5xc3x9710xe2x88x927 mol.
Preferable amount of sulfur sensitizer used in the present invention is 1xc3x9710xe2x88x924 to 1xc3x9710xe2x88x927 mol, and more preferably 1xc3x9710xe2x88x925 to 5xc3x9710xe2x88x927 mol per mol of silver halide.
As a preferable sensitizing method for the emulsion of the invention, selenium sensitization can be mentioned. As a selenium sensitize used in the invention, selenium compounds disclosed in hitherto published patents can be used as the selenium sensitizer in the present invention. In the use of labile selenium compound and/or nonlabile selenium compound, generally, it is added to an emulsion and the emulsion is agitated at high temperature, preferably 40xc2x0 C. or above, for a given period of time. Compounds described in, for example, Jpn. Pat. Appln. KOKOKU Publication No. (hereinafter referred to as JP-B-) 44-15748, JP-B-43-13489, JP-A""s-4-25832 and 4-109240 are preferably used as the unlabile selenium compound.
Specific examples of the labile selenium sensitizers include isoselenocyanates (for example, aliphatic isoselenocyanates such as allyl isoselenocyanate), selenoureas, selenoketones, selenoamides, selenocarboxylic acids (for example, 2-selenopropionic acid and 2-selenobutyric acid), selenoesters, diacyl selenides (for example, bis(3-chloro-2,6-dimethoxybenzoyl)selenide), selenophosphates, phosphine selenides and colloidal metal selenium.
The labile selenium compounds, although preferred types thereof are as mentioned above, are not limited thereto. It is generally understood by persons of ordinary skill in the art to which the invention pertains that the structure of the labile selenium compound as a photographic emulsion sensitizer is not so important as long as the selenium is labile and that the labile selenium compound plays no other role than having its selenium carried by organic portions of selenium sensitizer molecules and causing it to present in labile form in the emulsion. In the present invention, the labile selenium compounds of this broad concept can be used advantageously.
Compounds described in JP-B""s-46-4553, 52-34492 and 52-34491 can be used as the nonlabile selenium compound used in the present invention. Examples of the nonlabile selenium compounds include selenious acid, potassium selenocyanate, selenazoles, quaternary selenazole salts, diaryl selenides, diaryl diselenides, dialkyl selenides, dialkyl diselenides, 2-selenazolidinedione, 2-selenoxazolidinethione and derivatives thereof.
These selenium sensitizers are dissolved in water or in a single solvent or a mixture of organic solvents selected from methanol and ethanol and added at the time of chemical sensitization. Preferably, the addition is performed prior to the initiation of chemical sensitization. The use of the above selenium sensitizers is not limited to a single kind, but the combined use of two or more kinds may be acceptable. The combined use of a labile selenium compound and an unlabile selenium compound is preferred.
The addition amount of the selenium sensitizer for use in the invention, although varied depending on the activity of employed selenium sensitizer, the type and size of silver halide, the ripening temperature and time, etc., is preferably in the range of 1xc3x9710xe2x88x928 or more. More preferably, the amount is 1xc3x9710xe2x88x927 mol or more and 5xc3x9710xe2x88x925 mol or less per mol of silver halide. The temperature of chemical ripening in the use of a selenium sensitizer is preferably 40xc2x0 C. or more and 80xc2x0 C. or less. The pAg and pH are arbitrary. For example, with respect to pH, the effect of the present invention can be exerted even if it widely ranges from 4 to 9.
Selenium sensitization is preferably used in combination with sulfur sensitization or noble metal sensitization or both of them. Further, in the present invention, a thiocyanic acid salt is preferably added in the silver halide emulsion at the chemical sensitization. As the thiocyanate, potassium thiocyanate, sodium thiocyanate, ammonium thiocyanate, and the like are used. It is usually added by being dissolved in an aqueous solution or a water-soluble solvent. The addition amount per mol of silver halide is 1xc3x9710xe2x88x925 mol to 1xc3x9710xe2x88x922 mol, and more preferably 5xc3x9710xe2x88x925 mol to 5xc3x9710xe2x88x923 mol.
It is preferred that in the silver halide emulsion of the present invention, an appropriate amount of calcium ion and/or a magnesium ion be contained. Thereby, the grain shape is made better, the quality of an image is improved, and the preservation property is made better. The range of the appropriate amount is 400 to 2500 ppm for calcium and/or 50 to 2500 ppm for magnesium, and calcium is more preferably 500 to 2000 ppm and magnesium is 200 to 2000 ppm. Herein, 400 to 2500 ppm for calcium and/or 50 to 2500 ppm for magnesium means that at least one of calcium and magnesium is a concentration within the range prescribed. When the content of calcium or magnesium is higher than these values, it is not preferable that inorganic salts which calcium salt, magnesium salt, a gelatin or the like has preliminarily retained precipitate and become the cause of trouble at the manufacture of the photographic material. Herein, the content of calcium or magnesium is represented by weight converted to calcium atom or magnesium atom for all of the compounds containing calcium or magnesium such as a calcium ion, a magnesium ion, a calcium salt, a magnesium salt and the like, and represented by concentration based on the unit weight of the emulsion.
The adjustment of the calcium content in the silver halide tabular emulsion of the invention is preferably carried out adding the calcium salt at the chemical sensitization. The gelatin generally used at manufacturing an emulsion contains already calcium by 100 to 4000 ppm as a solid gelatin, and calcium may be adjusted by adding a calcium salt to the gelatin to be increased. Further, if necessary, after carrying out the desalting (removal of calcium) from the gelatin according to a known method such as a washing method with water or an ion exchange method or the like, the content can be also adjusted by a calcium salt. As the calcium salt, calcium nitrate and calcium chloride are preferable, and calcium nitrate is most preferable. Similarly, the adjustment of the magnesium content can be carried out adding a magnesium salt. As the magnesium salt, magnesium nitrate, magnesium sulfate and magnesium chloride are preferable, and magnesium nitrate is most preferable. As the quantitative determination method of calcium or magnesium, it can be determined by ICP emission spectral analysis method. Calcium and magnesium may be used alone and a mixture of both may be used. It is more preferable to contain calcium. The addition of calcium or magnesium can be carried out at the arbitrary period of the manufacturing steps of the silver halide emulsion, but is preferably from after the grain formation to just after completion of the spectral sensitization and the chemical sensitization, and more preferably after addition of a sensitizing dye. Further, it is preferable in particular to add after addition of a sensitizing dye and before carrying out the chemical sensitization.
Photographic emulsions used in the present invention can contain various compounds in order to prevent fog during the preparing process, storage, or photographic processing of a sensitized material, or to stabilize photographic properties. That is, it is possible to add many compounds known as antifoggants or stabilizers, e.g., thiazoles such as benzothiazolium salt; nitroimidazoles; nitrobenzimidazoles; chlorobenzimidazoles; bromobenzimidazoles; mercaptothiazoles; mercaptobenzothiazoles; mercaptobenzimidazoles; mercaptothiadiazoles; aminotriazoles; benzotriazoles; nitrobenzotriazoles; and mercaptotetrazoles (particularly 1-phenyl-5-mercaptotetrazole); mercaptopyrimidines; mercaptotriazines; a thioketo compound such as oxazolinethione; azaindenes such as triazaindenes, tetrazaindenes (particularly 4-hydroxy-substituted(1,3,3a,7)tetrazaindenes), and pentazaindenes. For example, compounds described in the specifications of U.S. Pat. Nos. 3,954,474 and 3,982,947 and JP-B-52-28660 can be used. One preferred compound is described in JP-A-63-212932. Antifoggants and stabilizers can be added at any of several different timings, such as before, during, and after grain formation, during washing with water, during dispersion after the washing, before, during, and after chemical sensitization, and before coating, in accordance with the intended application. The antifoggants and stabilizers can be added during preparation of an emulsion to achieve their original fog preventing effect and stabilizing effect. In addition, the antifoggants and stabilizers can be used for various purposes of, e.g., controlling the crystal habit of grains, decreasing the grain size, decreasing the solubility of grains, controlling chemical sensitization, and controlling the arrangement of dyes.
The photographic emulsion for use in the present invention is preferably subjected to a spectral sensitization with a methine dye or the like to thereby exert the effects of the invention. Examples of employed dyes include cyanine dyes, merocyanine dyes, composite cyanine dyes, composite merocyanine dyes, holopolar cyanine dyes, hemicyanine dyes, styryl dyes and hemioxonol dyes. Particularly useful dyes are those belonging to cyanine dyes, merocyanine dyes and composite merocyanine dyes. These dyes may contain any of nuclei commonly used in cyanine dyes as basic heterocyclic nuclei. Examples of such nuclei include a pyrroline nucleus, an oxazoline nucleus, a thiazoline nucleus, a pyrrole nucleus, an oxazole nucleus, a thiazole nucleus, a selenazole nucleus, an imidazole nucleus, a tetrazole nucleus and a pyridine nucleus; nuclei comprising these nuclei fused with alicyclic hydrocarbon rings; and nuclei comprising these nuclei fused with aromatic hydrocarbon rings, such as an indolenine nucleus, a benzindolenine nucleus, an indole nucleus, a benzoxazole nucleus, a naphthoxazole nucleus, a benzothiazole nucleus, a naphthothiazole nucleus, a benzoselenazole nucleus, a benzimidazole nucleus and a quinoline nucleus. These nuclei may have substituents on carbon atoms thereof.
The merocyanine dye or composite merocyanine dye may have a 5 or 6-membered heterocyclic nucleus such as a pyrazolin-5-one nucleus, a thiohydantoin nucleus, a 2-thioxazolidine-2,4-dione nucleus, a thiazolidine-2,4-dione nucleus, a rhodanine nucleus or a thiobarbituric acid nucleus as a nucleus having a ketomethylene structure.
These spectral sensitizing dyes may be used either individually or in combination. The spectral sensitizing dyes are often used in combination for the purpose of attaining supersensitization. Representative examples thereof are described in the specifications of U.S. Pat. Nos. 2,688,545, 2,977,229, 3,397,060, 3,522,052, 3,527,641, 3,617,293, 3,628,964, 3,666,480, 3,672,898, 3,679,428, 3,703,377, 3,769,301, 3,814,609, and 3,837,862, 4,026,707, GB""s 1,344,281 and 1,507,803, JP-B""s-43-4936 and 53-12375, and JP-A""s-52-110618 and 52-109925, the entire contents of which are incorporated herein by reference.
The emulsion used in the present invention may contain a dye which itself exerts no spectral sensitizing effect or a substance which absorbs substantially none of visible radiation and exhibits supersensitization, together with the above spectral sensitizing dye.
Further, the present invention is preferably used together with a technique of increasing light absorptivity by a spectrum sensitizing dye. For example, there is a method, by utilizing an intermolecular force, of causing more sensitizing dyes to adsorb to silver halide grain surfaces in comparison with those in a single-layer saturated absorption (that is, one-layer adsorption), or a method of adsorbing, to silver halide grains, a coupling dye having two or more chromophores which are not separately conjugated but coupled by a covalent bond. Among them, the present invention is preferably used together with the techniques disclosed in the following patent publications and specifications: JP-A""s-10-239789, 11-133531, 2000-267216, 2000-275772, 2001-75222, 2001-75247, 2001-75221, 2001-75226, 2001-75223, 2001-255615, 2002-23294, 10-171058, 10-186559, 10-197980, 2000-81678, 2001-5132, 2001-166413, 2002-49113, 64-91134, 10-110107, 10-171058, 10-226758, 10-307358, 10-307359, 10-310715, 2000-231174, 2000-231172, 2000-231173, and 2001-356442, and E.P. Nos. 985965A, 985964A, 985966A, 985967A, 1085372A, 1085373A, 1172688A, 1199595A, and 887700A1, the entire contents of which are incorporated herein by reference.
In particular, the present invention is preferably used together with the following patent publications: JP-A""s-10-239789, 2001-75222, and 10-171058.
The addition timing of the spectral sensitizing dye to the emulsion may be performed at any stage of the process for preparing the emulsion which is known as being useful. Although the doping is most usually conducted at a stage between the completion of the chemical sensitization and the coating, the spectral sensitizing dye can be added simultaneously with the chemical sensitizer to thereby simultaneously effect the spectral sensitization and the chemical sensitization as described in the specifications of U.S. Pat. Nos. 3,628,969 and 4,225,666. Alternatively, the spectral sensitization can be conducted prior to the chemical sensitization and, also, the spectral sensitizing dye can be added prior to the completion of silver halide grain precipitation to thereby initiate the spectral sensitization as described in JP-A-58-113928. Further, the above sensitizing dye can be divided prior to addition, that is, part of the sensitizing dye can be added prior to the chemical sensitization with the rest of the sensitizing dye added after the chemical sensitization as taught in the specification of U.S. Pat. No. 4,225,666. Still further, the spectral sensitizing dye can be added at any stage during the formation of silver halide grains according to the method disclosed in the specification of U.S. Pat. No. 4,183,756 and other methods.
The addition thereof may be set from 4xc3x9710xe2x88x926 to 8xc3x9710xe2x88x923 mol per mol of silver halide.
The silver halide color photosensitive material of the present invention is only required to have at least one light-sensitive layer on a support. Preferably, the silver halide photosensitive material is provided with at least one of a blue-sensitive layer, green-sensitive layer and red-sensitive layer on a support, and the number and order of the lightsensitive layer and non-lightsensitive layer are not particularly limited. Typical Example thereof is a silver halide photosensitive material having at least one light-sensitive unit layer comprising a plural of silver halide emulsion layers each having the substantially the same color sensitivity but different in speed. The light-sensitive unit layer is a unit layer having color sensitivity to any one of blue light, green light and red light. In a multi-layered silver halide color photosensitive material, the arrangement of the unit layer is generally, in the order, from a support, of a red-sensitive layer, green-sensitive layer and blue-sensitive layer. However, the arrangement order may be reversed depending on the purpose of the photographic material. And such an arrangement order that a light-sensitive layer having a different color sensitivity is sandwiched between layers having the same color sensitivity, may be acceptable.
A non-lightsensitive layer can be formed between the silver halide lightsensitive layers and as the uppermost layer and the lowermost layer.
These intermediate layers may contain, e.g., couplers and DIR compounds described in JP-A""s-61-43748, 59-113438, 59-113440, 61-20037 and 61-20038, and may contain color-mixing inhibitors as usually do so.
As for a plurality of silver halide emulsion layers constituting respective unit lightsensitive layer, a two-layered structure of high- and low-speed emulsion layers can be preferably used in this order so as to the speed becomes lower toward the support as described in the specification of DE (German Patent) 1,121,470 or GB 923,045, the entire contents of which are incorporated herein by reference. Usually, preferable order is such that the speed is gradually lowered toward the support. Further, a non-lightsensitive layer may be provided between respective silver halide emulsion layers. Also, as described in JP-A""s-57-112751, 62-200350, 62-206541 and 62-206543, the entire contents of which are incorporated herein by reference, layers can be arranged such that a low-speed emulsion layer is formed farther from a support and a high-speed layer is formed closer to the support.
More specifically, layers can be arranged from the farthest side from a support in the order of low-speed blue-sensitive layer (BL)/high-speed blue-sensitive layer (BH)/high-speed green-sensitive layer (GH)/low-speed green-sensitive layer (GL)/high-speed red-sensitive layer (RH)/low-speed red-sensitive layer (RL), the order of BH/BL/GL/GH/RH/RL or the order of BH/BL/GH/GL/RL/RH.
In addition, as described in JP-B-55-34932, the entire contents of which are incorporated herein by reference, layers can be arranged from the farthest side from a support in the order of blue-sensitive layer/GH/RH/GL/RL. Furthermore, as described in JP-A""s-56-25738 and 62-63936, the entire contents of which are incorporated herein by reference, layers can be arranged from the farthest side from a support in the order of blue-sensitive layer/GL/RL/GH/RH.
As described in JP-B-49-15495, the entire contents of which are incorporated herein by reference, three layers can be arranged such that a silver halide emulsion layer having the highest sensitivity is arranged as an upper layer, a silver halide emulsion layer having sensitivity lower than that of the upper layer is arranged as an interlayer, and a silver halide emulsion layer having sensitivity lower than that of the interlayer is arranged as a lower layer; i.e., three layers having different sensitivities can be arranged such that the sensitivity is sequentially decreased toward the support. Even when a layer structure is constituted by three layers having different sensitivities, these layers can be arranged in the order of medium-speed emulsion layer/high-speed emulsion layer/low-speed emulsion layer from the farthest side from a support in a layer sensitive to one color as described in JP-A-59-202464, the entire contents of which are incorporated herein by reference.
In addition, the order of high-speed emulsion layer/low-speed emulsion layer/medium-speed emulsion layer or low-speed emulsion layer/medium-speed emulsion layer/high-speed emulsion layer can be adopted. Furthermore, the arrangement can be changed as described above even when four or more layers are formed.
In order to improve the color reproducibility, a donor layer (CL) of an interlayer effect having a spectral sensitivity distribution different from the main lightsensitive layers BL, GL and RL as described in the specifications of U.S. Pat. Nos. 4,663,271, 4,705,744 and 4,707,436 and JP-A""s-62-160448 and 63-89850, the entire contents of which are incorporated herein by reference, is preferably arranged adjacent to or close to the main lightsensitive layers.
In the silver halide color photosensitive material of the present invention, various additives can be used in conformity with the object thereof.
These additives are described in detail in Research Disclosure Item 17643 (December 1978), Item 18716 (November 1979) and Item 308119 (December 1989), all the contents of which are incorporated herein by reference. A summary of the locations where they are described will be listed in the following table.
In order to inhibit deterioration in photographic properties due to formaldehyde gas, a compound capable of reacting with and solidifying formaldehyde as disclosed in U.S. Pat. Nos. 4,411,987 and 4,435,503 can be incorporated in the light-sensitive material.
Various color couples may be used in the present invention, and the specific examples thereof are described in the patents described in the patents described in the aforementioned Research Disclosure No. 17643, VII-C to G and No. 307105, VII-C to G.
Preferred yellow couplers are those described in, for example, specifications of U.S. Pat. Nos. 3,933,051, 4,022,620, 4,326,024, 4,401,752 and 4,248,961, JP-B-58-10739, GB""s 1,425,020 and 1,476,760, U.S. Pat. Nos. 3,973,968, 4,314,023 and 4,511,649, and EP 249,473A.
Particularly preferred magenta couplers are 5-pyrazolone and pyrazoloazole compounds. Particularly preferred are those described in the specifications of U.S. Pat. Nos. 4,310,619 and 4,351,897, EP 73,636, U.S. Pat. Nos. 3,061,432 and 3,725,067, Research Disclosure No. 24220 (June, 1984), JP-A-60-33552, Research Disclosure No. 24230 (June, 1984), JP-A""s-60-43659, 61-72238, 60-35730, 55-118034 and 60-185951, U.S. Pat. Nos. 4,500,630, 4,540,654 and 4,556,630, and International Publication No. WO 88/04795.
The cyan couplers usable in the present invention are phenolic and naphtholic couplers. Particularly preferred are those described in the specifications of U.S. Pat. Nos. 4,052,212, 4,146,396, 4,228,233, 4,296,200, 2,369,929, 2,801,171, 2,772,162, 2,895,826, 3,772,002, 3,758,308, 4,334,011 and 4,327,173, West German Patent Published Application No. 3,329,729, EP""s 121,365A and 249,453A, U.S. Pat. Nos. 3,446,622, 4,333,999, 4,775,616, 4,451,559, 4,427,767, 4,690,889, 4,254,212 and 4,296,199, and JP-A-61-42658.
Typical examples of the polymerized color-forming couplers are described in, for example, the specifications of U.S. Pat. Nos. 3,451,820, 4,080,211, 4,367,282, 4,409,320 and 4,576,910, GB 2,102,137 and EP 341,188A.
The couplers capable of forming a colored dye having a suitable diffusibility are preferably those described in the specifications of U.S. Pat. No. 4,366,237, GB 2,125,570, EP 96,570 and West German Patent (Publication) No. 3,234,533.
Colored couplers used for compensation for unnecessary absorption of the colored dye are preferably those described in Research Disclosure No. 17643, VII-G and No. 307105, VII-G, and the specifications of U.S. Pat. No. 4,163,670, JP-B-57-39413, U.S. Pat. Nos. 4,004,929 and 4,138,258 and GB 1,146,368. Other couplers preferably used herein include couplers capable of compensating for an unnecessary absorption of the colored dye with a fluorescent dye released during the coupling as described in U.S. Pat. No. 4,774,181 and couplers having, as a removable group, a dye precursor group capable of forming a dye by reacting with a developing agent as described in the specification of U.S. Pat. No. 4,777,120.
Further, compounds that release a photographically useful residue during a coupling reaction are also preferably usable in the present invention. DIR couplers which release a development inhibitor are preferably those described in the patents shown in the above described RD 17643, VII-F and No. 307105, VII-F as well as those described in JP-A""s-57-151944, 57-154234, 60-184248, 63-37346 and 63-37350 and U.S. Pat. Nos. 4,248,962 and 4,782,012.
The couplers which release a nucleating agent or a development accelerator in the image-form in the development step are preferably those described in GB""s 2,097,140 and 2,131,188 and JP-A""s-59-157638 and 59-170840. Further, compounds capable of releasing a fogging agent, development accelerator, solvent for silver halides, etc. upon the oxidation-reduction reaction with an oxidized developing agent as described in JP-A""s-60-107029, 60-252340, 1-44940 and 1-45687 are also preferred.
Other compounds usable for the photosensitive material according to the present invention include competing couplers described in U.S. Pat. No. 4,130,427, polyequivalent couplers described in U.S. Pat. Nos. 4,283,472, 4,338,393 and 4,310,618, DIR redox compound-releasing couplers, DIR coupler-releasing couplers, DIR coupler-releasing redox compounds and DIR redox-releasing redox compounds described in JP-A""s-60-185950 and 62-24252, couplers which release a dye that restores the color after coupling-off as described in EP""s 173,302 A and 313,308 A, ligand-releasing couplers described in U.S. Pat. No. 4,555,477, leuco dye-releasing couplers described in JP-A-63-75747 and fluorescent dye-releasing couplers described in U.S. Pat. No. 4,774,181.
The couplers used in the present invention can be incorporated into the photosensitive material by various known dispersion methods.
High-boiling solvents used for an oil-in-water dispersion method are described in, for example, U.S. Pat. No. 2,322,027.
The high-boiling organic solvents having a boiling point under atmospheric pressure of at least 175xc2x0 C. and usable in the oil-in-water dispersion method include, for example, phthalates (such as dibutyl phthalate, dicyclohexyl phthalate, di-2-ethylhexyl phthalate, decylphthalate, bis(2,4-di-t-amylphenyl)phthalate, bis(2,4-di-t-amylphenyl)isophthalate and bis(1,1-diethylpropyl)phthalate); phosphates and phosphonates (such as triphenyl phosphate, tricresyl phosphate, 2-ethylhexyldihenyl phosphate, tricyclohexyl phosphate, tri-2-ethylhexyl phosphate, tridodecyl phoshate, tributoxyethyl phosphate, trichloropropyl phosphate and di-2-ethylhexylphenyl phosphate); benzoates (such as 2-ethylhexyl benzoate, dodecyl benzoate and 2-ethylhexyl-p-hydroxybenzoate); amides (such as N,N-diethyldodecaneamide, N,N-diethyllaurylamide and N-tetradecylpyrrolidone); alcohols and phenols (such as isostearyl alcohol and 2,4-di-tert-amylphenol); aliphatic carboxylates (such as bis(2-ethylhexyl)sebacate, dioctyl azelate, glycerol tributyrate, isostearyl lactate and trioctyl citrate); aniline derivatives (such as N,N-dibutyl-2-butoxy-5-tert-octylaniline) and hydrocarbons (such as paraffin, dodecylbenzene and diisopropylnaphthalene).
Co-solvents usable in the present invention include, for example, organic solvents having a boiling point of at least about 30xc2x0 C., preferably 50 to about 160xc2x0 C. Typical examples of them include ethyl acetate, butyl acetate, ethyl propionate, methyl ethyl ketone, cyclohexanone, 2-ethoxyethyl acetate and dimethylformamide.
The steps and effects of the latex dispersion method and examples of the lates usable for the impregnation are described in, for example, U.S. Pat. No. 4,199,363 and West German Patent Application (OLS) Nos. 2,541,274 and 2,541,230.
The color photosensitive material of the present invention preferably contains phenethyl alcohol or an antiseptic or mold-proofing agent described in JP-A""s-63-257747, 62-272248 and 1-80941 such as 1,2-benzoisothiazolin-3-one, n-butyl p-hydroxybenzoate, phenol, 4-chloro-3,5-dimethylphenol, 2-phenoxyethanol or 2-(4-thiazolyl)benzimidazole.
The present invention is applicable to various color photosensitive materials such as ordinary color negative films, cinema color negative films, reversal color films for slides or televisions, color papers, positive color films and reversal color papers. The present invention may be particularly preferably used as color dupe films.
Suitable supports usable in the present invention are described, for example, on page 28 of the above-described RD. No. 17643, from right column, page 647 to left column, page 648 of RD. No. 18716 and on page 879 of RD. No. 307105.
In the photosensitive material of the present invention, hydrophilic colloid layers (called xe2x80x9cback layersxe2x80x9d) having a total dried film thickness of 2 to 20 xcexcm are preferably formed on the side opposite to the side having emulsion layers. The back layers preferably contain the above light absorbent, filter dye, ultraviolet absorbent, antistatic agent, film hardener, binder, plasticizer, lubricant, coating aid and surfactant. The swelling ratio of the back layers is preferably 150% to 500%.
The photosensitive material of the present invention can be developed by conventional methods described in RD. No. 17643, pages 28 and 29; RD. No. 18716, page 651, left to right columns; and RD No. 307105, pages 880 and 881.
A photographic emulsion layer is generally bleaching processed after being color development processed. A bleaching process and a fixing process may be carried out at the same time (bleach-fixing process) or may be performed separately. A processing method comprising carrying out a bleach-fixing process after a bleaching process can be adopted for further rapid processing. Also, processing in two successive bleach-fixing baths, fixing process before bleach-fixing process, or bleaching process after bleach-fixing process may optionally be selected according to purposes. Compounds of polyvalent metals such as iron(III), peracids, quinones, and nitro compounds are used as a bleaching agent. Representative examples of bleaching agents which are preferably used in the present invention include a complex salt such as organic complex salts of iron(III) with aminopolycarboxylic acids, e.g., ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, cyclohexanediaminetetraacetic acid, methyliminodiacetic acid, 1,3-diaminopropanetetraacetic acid, and glycol ether diaminetetraacetic acid, or citric acid, tartaric acid or malic acid. The use of aminopolycarboxylic acid iron(III) complex salts such as ethylenediaminetetraacetic acid iron(III) complex salts and 1,3-diaminopropanetetraacetic acid iron(III) complex salts is particularly preferred of them from the point of providing rapid processing and preventing environmental pollution. Further, aminopolycarboxylic acid iron(III) complex salts are particularly useful in both of a bleaching solution and a bleach-fixing solution. The pH of the bleaching solution or the bleach-fixing solution in which these aminopolycarboxylic acid iron(III) complex salts are included is generally from 4.0 to 8, but lower pH can be used to speed up the processing.
Bleaching accelerators can be used, if necessary, in the bleaching solution, the bleach-fixing solution, or the prebaths thereof. Specific examples of useful bleaching accelerators are disclosed in the following specifications: the compounds which have a mercapto group or a disulfido group disclosed in U.S. Pat. No. 3,893,858, German Patents 1,290,812, 2,059,988, JP-A""s-53-32736, 53-57831, 53-37418, 53-72623, 53-95630, 53-95631, 53-104232, 53-124424, 53-141623, and 53-28426, and RD, No. 17129 (July, 1978); the thiazolidine derivatives disclosed in JP-A-50-140129; the thiourea derivatives disclosed in JP-B-45-8506, JP-A-52-20832, JP-A-53-32735, and U.S. Pat. No. 3,706,561; the iodides disclosed in German Patent 1,127,715 and JP-A-58-16235; the polyoxyethylene compounds disclosed in German Patents 966,410 and 2,748,430; the polyamine compounds disclosed in JP-B-45-8836; the other compounds disclosed in JP-A""s-49-40943, 49-59644, 53-94927, 54-35727, 55-26506 and 58-163940; and bromide ions. The compounds which have a mercapto group or a disulfido group are preferred from the point of providing large accelerating effect, and those disclosed in U.S. Pat. No. 3,893,858, German Patent 1,290,812 and JP-A-53-95630 are particularly preferred of all. Further, the compounds disclosed in U.S. Pat. No. 4,552,834 are also preferred. These bleaching accelerators can be included in photographic materials. These bleaching accelerators are especially effective when bleach-fixing color photographic materials for photographing.
It is preferred to include organic acids in a bleaching solution and a bleach-fixing solution, in addition to the above compounds, for inhibiting bleaching stain. Particularly preferred organic acids are compounds having an acid dissociation constant (pKa) of from 2 to 5, specifically, acetic acid, propionic acid, and hydroxyacetic acid are preferred.
Thiosulfate, thiocyanate, thioether based compounds, thioureas, and a large amount of iodide can be used as the fixing agent which is used in a fixing solution and a bleach-fixing solution, but thiosulfate is generally used, in particular, ammonium thiosulfate can be most widely used. Further, the combined use of thiosulfate with thiocyanate, thioether based compounds and/or thiourea is also preferred. As preservatives for a fixing solution and a bleach-fixing solution, sulfite, bisulfite, carbonyl-bisulfite addition products or the sulfinic acid compounds disclosed in EP 294769A are preferred. Moreover, aminopolycarboxylic acids and organic phosphonic acids are preferably added to a fixing solution and a bleach-fixing solution for stabilizing the solutions.
In the present invention, compounds having a pKa of from 6.0 to 9.0 are preferably added to a fixing solution or a bleach-fixing solution for controlling pH, preferably imidazoles such as imidazole, 1-methylimidazole, 1-ethylimidazole and 2-methylimidazole, in an amount of from 0.1 to 10 mol per liter.
The total processing time of the desilvering process is preferably shorter in the range not generating a desilvering failure. The desilvering processing time is preferably from 1 minute to 3 minutes and more preferably from 1 minute to 2 minutes. Further, the processing temperature is generally from 25xc2x0 C. to 50xc2x0 C., and preferably from 35xc2x0 C. to 45xc2x0 C. In the preferred temperature range, the desilvering rate is increased and the occurrence of staining after processing is effectively prevented.
The color photosensitive material of the present invention may be built in (incorporated) a color-developing agent, for the purpose of simplification of the processing and advances in processing speed. For building in, various kinds of precursors of the color developing agent are preferably used. Examples of the precursor include indoaniline-series compounds described in U.S. Pat. No. 3,342,597; Schiff base type compounds described in U.S. Pat. No. 3,342,599, R.D. No. 14850 and ibid. No. 15159; aldol compounds described in R.D. No. 13924; metal complex salts described in U.S. Pat. No. 3,719,492; and urethane-series compounds described in JP-A-53-135628.
The color photosensitive material of the present invention may be built in various kinds of 1-phenyl-3-pyrazolidones in order to accelerate color development, as occasion demands. Typical are described in JP-A""s-56-64339, 57-144547, and 58-115438.
The silver halide photosensitive material of the present invention may be applied to heat development photosensitive material described in the specifications of U.S. Pat. No. 4,500,626, JP-A""s-60-133449, 59-218443 and 61-238056, and EP 210,660A2.
The photosensitive material of the present invention described above can more easily express the advantages when it is used for lens-equipped film units disclosed in JP-B-2-32615 and Jpn. U.M. Appln. KOKOKU Pub. No. 3-39784.